Answer:
m = 69.9 kg
Explanation:
The mass and the weight of an object are two different quantities. Mass is basically the amount of matter that is present in a body. It remains same everywhere in the universe and measured in kilograms.
Weight is basically a force. It is the force by which earth attracts everything towards itself. The weight of an object changes from planet to planet, with the change in value of the gravitational acceleration (g).
Therefore, the relation between mass and weight of an object is given by the following formula:
W = mg
m = W/g
where,
m = mass = ?
W = Weight = 685 N
g = 9.8 m/s²
Therefore,
m = (685 N)/(9.8 m/s²)
m = 69.9 kg
The mass of an object that experience a gravitational force of 685N near the earth is approximately 69.90 kg
The mass and weight are 2 different quantities.
The mass of a substance is the amount of matter present in it. Mass is measured in kilograms
The Weight is the measurement of gravitational pull of planet towards the object. Therefore, weight is a force and measured in Newton.
Mathematically, the weight can be express as follows
W = mg
where
m = mass
g = acceleration due to gravity = 9.8 m/s²
Therefore,
685 = 9.8 × m
m = 685 / 9.8
m = 69.8979591837
m = 69.90 kg
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The planet Mercury takes 0.24 sidereal years to go around the sun. What is the distance from the center of Mercury to the center of the sun
Answer:
5.77×10¹⁰ m
Explanation:
From the question,
Applying
Kepler's third law
P² = d³...................... Equation 1
Where P = Planet's period, d = distance between the center of the planet and the sun.
make d the subject of the formula n equation 1
d = [tex]\sqrt[3]{P^{2} }[/tex].................. Equation 2
Given: P = 0.24 sidereal.
Substitute the value of P into equation 2
d = [tex]\sqrt[3]{0.24^{2} }[/tex]
d = 0.386 Au
d = 0.386×1.496×10¹¹
d = 5.77×10¹⁰ m
1. What is the longest-wavelength EM radiation that can eject a photoelectron from silver, given that the binding energy is 4.73 eV? Is this in the visible range?
2. Find the longest-wavelength photon that can eject an electron from potassium, given that the binding energy is 2.24 eV. Is this visible EM radiation?
Answer:
1. λ = 2.626 x 10⁻⁷ m = 262.6 nm
This wavelength is not in visible range. It lies in Ultra Violet Region.
2. λ = 5.546 x 10⁻⁷ m = 554.6 nm
This wavelength is in visible range.
Explanation:
The binding energy of in photoelectric effect is also known as work function. The formula for this is given as follows:
Binding Energy = Work Function = hc/λ
λ = hc/Work Function --------------- equation (1)
where,
h = Plank's Constant = 6.626 x 10⁻³⁴ J.s
c = speed of light = 3 x 10⁸ m/s
λ = longest wavelength capable of ejecting electron = ?
(1)
Here,
Work Function = (4.73 eV)(1.6 x 10⁻¹⁹ J/1 eV) = 7.568 x 10⁻¹⁹ J
Therefore,
λ = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(7.568 x 10⁻¹⁹ J)
λ = 2.626 x 10⁻⁷ m = 262.6 nm
This wavelength is not in visible range. It lies in Ultra Violet Region.
(2)
Here,
Work Function = (2.24 eV)(1.6 x 10⁻¹⁹ J/1 eV) = 3.584 x 10⁻¹⁹ J
Therefore,
λ = (6.626 x 10⁻³⁴ J.s)(3 x 10⁸ m/s)/(3.584 x 10⁻¹⁹ J)
λ = 5.546 x 10⁻⁷ m = 554.6 nm
This wavelength is in visible range.
Suppose the same car had at one point an acceleration of 12m/s^2 and an initial velocity of 8m/s. After 2 seconds, what would be the car's final velocity
Answer: 32 m/s
Explanation: v = u + at
= 8 + 12*2
= 8 + 24
= 32 m/s
A motorcycle is following a car that is traveling at a constant speed on a straight highway. Initially, the car and the motorcycle are both traveling at the same speed of 19.0 m/s, and the distance between them is 52.0 m. After t1 = 5.00 s, the motorcycle starts to accelerate at a rate of 5.00 m/s2. How long does it take from the moment when the motorcycle starts to accelerate until it catches up with the car?
Answer:
t=2.14s
Explanation:
Since it asks us for the time it takes from the moment it starts accelerating, the first 5 seconds of movement mentioned is irrelevant here.
Next it'd be simple just to use the kinematic equation involving distance, time, and velocity:
∆d=V₀t+at²/2
From here we can move the change in distance over and use the quadratic formula to solve for time.
My work is in the attachment. Comment with any questions.
Fluid flows at 2.0 m/s through a pipe of diameter 3.0 cm. What is the volume flow rate of the fluid?
Answer:
The volume flow rate of the pipe is 1.41 x 10⁻³ m³/s
Explanation:
Given;
velocity of the fluid, v = 2.0 m/s
diameter of the pipe, d = 3.0 cm = 0.03 m
The volume flow rate is given by;
Q = Av
Where;
A is the area of the pipe
v is the velocity of the fluid
circular surface Area of the pipe is given by;
A = ¹/₄ πd²
A = ¹/₄ π(0.03)² = 7.07 x 10⁻⁴ m²
Q = (7.07 x 10⁻⁴)(2)
Q = 1.41 x 10⁻³ m³/s
Therefore, the volume flow rate of the pipe is 1.41 x 10⁻³ m³/s
how to protect the ozone layer?
Answer:
[tex]\huge{\purple{\underline{\underline{\bf{\pink{Answer}}}}}}[/tex]
we have to protect ozone layer because it is like blanket for earth . It protects the earth form uv rays that are coming from the sunwe have to take some preventive. measures like
Use ecofriendly things that Doesnot contain (cfc) . It is the major reason for ozone DeplitionEffects of uv rays
Uv rays are very harmful . If it directly comes in contact with human it cause skin cancer , eyes irritation etc.Hope it helps.
In experimental design: What are
the two groups?
Answer:
The correct answer is : a special type of experimental design where subject divides in two groups according their treatment setting.
Explanation:
A two group is a experimental design two groups are the two different groups of subjects divided by the researcher for comparing the data and result to establish relation in variables.
In normal case, one of the two groups one is a group of subjects who get treatment known as experiment or treatment group while other group is known as control group without treatment.
Thus, the correct answer is : a special type of experimental design where subject divides in two groups according their treatment setting.
a particular kind of experimental design in which the subjects are split into two groups based on the treatment environment. A two-group design is an experiment.
The researcher separated the participants into two groups and then compared the data and results to identify any relationships between the variables.
In a typical scenario, one of the two groups is made up of participants in an experiment or treatment group who receive care, while the other group is referred to as the control group who do not receive care.
Therefore, a particular kind of experimental design where subjects are divided into two groups according to their course of therapy.
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1. Explain the difference between accuracy and precision 2. Name a statistical quantity that can be used to indicate an accuracy level. 3. Name a statistical quantity that can be used to indicate a precision level. 4. To what level of accuracy (1 cm, 0.1 cm, 0.01 cm. 0.001 cm) can the ruler used to measure the lengths of the pencil in the above example be read?
Answer:
Accuracy explains the closeness or nearness of a measured or studied quantity to the actual value while precision explains the ability of a measuring device to get the same measured value when measured repeatedly
2 Accuracy is determined by percentage error while precision is by taking the ratio of standard deviation with the individual measurements
3. The accuracy of the ruler is 0.001 cm because that's the least measurement it can take
The north pole of a bar magnet points towards a thin circular coil of wire containing 40 turns. The magnet is moved away from the coil, so that the ux through one turn inside the coil decreases by ∆Φ = 0.3 T.m2 in a time ∆t = 0.2 s. What is the average EMF induced in the (whole) coil during this time interval? Viewed from the side opposite of the bar magnet (from the right), does the induced current run clockwise or counterclockwise? Explain briey. [2 p.]
Answer:
60 V
Current will flow anticlockwise from the right side of the magnet.
Explanation:
The number of turns on the coil = 40 turns
The magnetic flux changes by ∆Φ = 0.3 T.m^2
The time changes by ∆t = 0.2 s
The induced emf can be gotten as
E = N∆Φ/∆t
substituting values, we have
E = (40 x 0.3)/0.2 = 60 V
If we move the magnet away from the coil, then from Lenz law, the induced current on the coil will try to oppose the motion of the magnet by attracting the magnet towards the coil. For this to happen, the coil must possess the equivalent of a magnetic south pole. For the equivalent of a magnetic south pole, the current on the coil will flow in the clockwise direction when viewed from the left side of the magnet. This will appear as an anticlockwise direction, when viewed from the right side of the magnet.
Runner A is initially 6.0 km west of a flagpole and is running with a constant velocity of 9.0 km/h due east. Runner B is initially 5.0 km east of the flagpole and is running with a constant velocity of 8.0 km/h due west. What will be the distance of the two runners from the flagpole when their paths cross
Answer:
From the data we know that runner A and runner B are 11 km apart from the start because (6+5) km
So the runner from the east direction has distance as unknown km, rate= 9 k/h ; time= d/r=x/9 hr
So runner towards the west will be
distance = 11-x, rate= 8 k/h, time = d/r = (11-x)/8
So equating east and west time we have
x/9= (11-x)/8
8x=99-9x
17x=99
x=5.92 km
That is the distance covered by runner towards the east and he will meet the runner toward the west at
6-5.92=0.08 km west of the flagpole.
Which number below equals 129000? * *
Answer:
0.1
Explanation:
A light plane must reach a speed of 33 m/s for takeoff. How long a runway is needed if the constant acceleration is 3.0 m/s2
Answer:
181.5 m
Explanation:
From the question,
Applying the equation of motion,
v² = u²+2as................. Equation 1
Where a = acceleration of the light plane, v = final velocity of the light plane, u = initial velocity of the light plane, s = length of the runway.
make s the subject of formula in equation 1
s = (v²-u²)/2a.............. Equation 2
Given: v = 33 m/s, u = 0 m/s(from rest), a = 3.0 m/s²
Substitute these values into equation 2
s = (33²-0²)/(2×3)
s = 1089/6
s = 181.5 m
A car is traveling at a speed of 80 ft/s when the brakes are suddenly applied, causing a constant deceleration of 10 ft/s2. Determine the time required to stop the car and the distance traveled before stopping.
Answer:
Time taken = 8 second
Distance traveled = 320 ft
Explanation:
Given:
Initial velocity (u) = 80 ft/s
Acceleration (a) = (-)10 ft/s²
Final velocity (v) = 0 ft/s
Find:
Time taken
Distance traveled
Computation:
v = u + at
0 = 80 + (-10)(t)
t = 8 second
Time taken = 8 second
s = ut + (1/2)(a)(t)²
s = (80)(8) + (1/2)(-10)(8)²
s = 320 ft
Distance traveled = 320 ft
Water condenses on the side of a glass of ice water because the glass's temperature is below the dew point temperature.A. TrueB. False
Answer:
A. True
Explanation:
Water exists in the air in its gaseous form. If this gaseous water is cooled sufficiently enough below its dew point, it will condense into liquid water. This is what happens to the body of a glass filled with cold water. The glass's temperature drops the temperature of the air immediately around it, cooling it below dew point temperature. This causes water to condense on the body of the glass.
1. How does the de Broglie wavelength of an electron change if its momentum increases?
a. The de Broglie wavelength of the electron increases.
b. The de Broglie wavelength of the electron decreases.
c. The de Broglie wavelength of the electron is unchanged.
2. How does the de Broglie wavelength of an electron change if its kinetic energy decreases?
a. The de Broglie wavelength of the electron increases.
b. The de Broglie wavelength of the electron decreases.
c. The de Broglie wavelength of the electron is unchanged.
Answer:
1. The de Broglie wavelength of the electron decreases if its momentum increases.
b. The de Broglie wavelength of the electron decreases is the correct answer
2. The de Broglie wavelength of the electron increases as the kinetic energy decreases.
a. The de Broglie wavelength of the electron increases is the correct option
Explanation:
1. The relationship between de Broglie wavelength, λ and momentum ρ is given by
λ = h/ρ
Where λ is the de Broglie wavelength
h is Planck's constant and
ρ is the momentum
From the formula, the de Broglie wavelength, λ varies inversely with the momentum, ρ. Hence, as the de Broglie wavelength increases the momentum decreases; similarly, as the de Broglie wavelength decreases, the momentum increases.
For question 1, The de Broglie wavelength of the electron decreases if its momentum increases.
b. The de Broglie wavelength of the electron decreases is the correct answer
2. From
λ = h/ρ
ρ = mv
∴ λ = [tex]\frac{h}{mv}[/tex]
Where m is mass
and v i velocity
Recall that Kinetic energy K.E is given by
K.E = [tex]\frac{1}{2}mv^{2}[/tex]
[tex]E_{K} = \frac{1}{2}mv^{2}[/tex]
[tex]E_{K}[/tex] is the kinetic energy
∴ [tex]v = \sqrt{\frac{2E_{K} }{m} }[/tex]
Now we will evaluate [tex]mv[/tex]
[tex]mv = m \sqrt{\frac{2E_{K} }{m} }\\mv = \sqrt{m^{2} }.\sqrt{\frac{2E_{K} }{m} }\\ mv = \sqrt{\frac{2m^{2}E_{K} }{m} } \\mv = \sqrt{{2mE_{K} }[/tex]
∴ λ = [tex]\frac{h}{mv}[/tex] becomes
λ = [tex]\frac{h}{\sqrt{2mE_{K} } }[/tex]
This equation shows the relationship between the de Broglie wavelength and kinetic energy, [tex]E_{K}[/tex]
From the equation, de Broglie wavelength varies inversely with kinetic energy. That is, as the de Broglie wavelength increases the kinetic energy decreases; similarly, as the de Broglie wavelength decreases, the kinetic increases.
For question 2, The de Broglie wavelength of the electron increases as the kinetic energy decreases.
a. The de Broglie wavelength of the electron increases is the correct option
A swimmer heads for the opposite bank of a river. Make a sketch showing the swimmer's two velocities and the resultant velocity. (Assume the river flows in the +x direction and the opposite bank is in the +y direction.)
Answer:
v = √ (v₁² - vₓ²)
θ = sin⁻¹ (vₓ / v₁)
Explanation:
This is a speed composition exercise in kinematics, in the adjoint we can see the swimmer with speed v₁ and the river with speed vₓ, the resulting speed is v
To find these values we can use the Pythagorean theorem
v₁² = v² + vₓ²
v = √ (v₁² - vₓ²)
the direction the swimmer should take is
sin θ = vₓ / v₁
θ = sin⁻¹ (vₓ / v₁)
LAGOS PROVINCE 10
TEXT:
TOPIC
SPEAKER
DATE:
s
Sussend
5 Gorg
ve
Cand
care. The pre
density is haragin
cable?
s
terson
Answer:
Explanation:
what?
What replaced copper wires in long distance communicationas they are cheaper and less bulky than copper cables carrying the same information
Answer:
Optical Fiber
Explanation:
Optical fibers have replaced copper wire in long distance communication as they are cheaper and less bulky than copper cables carrying the same information. Optical Fibers transfer information from one place to another by sending pulses of infrared light signals. Light act as carrier waves.
A 550 lines/mm diffraction grating is illuminated by light of wavelength 500 nm . Part A How many bright fringes are seen on a 3.8-m-wide screen located 2.2 m behind the grating?
Answer:
7bright fringes
Explanation:
First we know that
Sinစ m,max= Mmax, x lambda/d
To find Mmax
Sin90° = Mmax x lambda/d = 1
So
Mmax= d/ lambda
= lambda= 500nm
d= 1/550mm
So
= 1.8 x10-6/500x 10^-9m
= 3.6
So m is approx 3
So 3 bright fringes above below and the central bright fringe itself making 7bright fringes
You are comparing a reaction that produces a chemical change and one that produces a physical change. What evidence could you use to determine which type of change is occurring?
Answer:
''
Explanation:
A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding. Often, physical changes can be undone, if energy is input.
Answer:
If the reaction is a chemical change, new substances with different properties and identities are formed. This may be indicated by the production of an odor, a change in color or energy, or the formation of a solid.
At what angle should the axes of two Polaroids be placed so as to reduce the intensity of the incident unpolarized light to 1515.
Complete Question
At what angle should the axes of two Polaroids be placed so as to reduce the intensity of the incident unpolarized light to 1/5.
Answer:
The angle is
Explanation:
From the question we are told that
The light emerging from second Polaroid is 1/5 the unpolarized
Generally the intensity of light emerging from the first Polaroid is mathematically represented as
[tex]I_1 = \frac{I_o}{ 2 }[/tex]
Generally from the Malus law the intensity of light emerging from the second Polaroid is mathematically represented
[tex]I_2 = I_1 cos^2 (\theta )[/tex]
=> [tex]cos^2 (\theta ) = \frac{I_2}{I_1 }[/tex]
=> [tex]cos (\theta) = \sqrt{ \frac{I_2}{I_1} }[/tex]
From the question [tex]I_2 = \frac{I_o}{5}[/tex]
[tex]cos (\theta) = \sqrt{ \frac{ \frac{ I_o}{5} }{\frac{I_o}{2} } }[/tex]
[tex]cos (\theta) = \sqrt{ \frac{2}{5} }[/tex]
=> [tex]\theta = cos ^{-1} [\sqrt{\frac{2}{5}} ][/tex]
=> [tex]\theta = 50.77^o[/tex]
state the basic law of charges
Answer:
Things that have the same charge push each other away (they repel each other). This is called the Law of Charges. … Things that have more electrons than protons are negatively charged, while things with fewer electrons than protons are positively charged. Things with the same charge repel each other.
Explanation:
One of the great upcoming sports in the Olympics is the sport of curling. Write a brief essay on the uses of momentum collisions in curling. Be sure to discuss the importance of massive stones and of going last. in at least 150 words
The Olympic sport of curling is one that is practically designed to show Physics in motion. Curling is a sport in which two teams alternate sliding smoothed stone pucks down an ice rink court with the intent to seat their stone closest to the center of the target (called the house). Each team has eight stones, meaning that the team that goes second has the (could be) massive advantage of sending the last stone.
The mass of the stone is important in that the more massive a stone (m) and the speed at which it travels (v) dictates it's momentum (momentum=mxv). As the curling stone slides down the ice (which is relatively frictionless unless acted upon by other players or objects) and having inertia, continues in it's straight course (again, unless acted upon by outside forces). If the stone hits another stone, it transfers some of its momentum in an elastic collision to that stone and the original stone is deflected in a calculable manner.
Collisions are used in the game to either clear opponent's stones from the house or out of their defensive positions, or to make adjustments to one's stones present in the house, all based on the momentum of the moving stone, and its transference.
If a negative point charge is placed at PP without moving the original charges, the net electrical force the charges ±Q±Q will exert on it is
Answer:
hello your question is incomplete below is the complete question
point p is equidistant from two point charges +-Q of equal magnitude if a negative point charge is places at P without moving the original charges the net electrical force the charges +-Q will exert on it is A. directly upward B. directly downward C. zero D. directly to the right E. directly to the left why is it A?????
Answer : Directly upward
Explanation:
The direction of the resultant force acting on the charge placed at P will be in the upward direction. this is because the net electric force at point p due to the opposite charges will be acted in the downward direction. If the negative charge is placed at point P, then the direction of the resultant force acting on the charge placed at P will be in the opposite direction to that of the field. i.e in the upward direction
7: A 2 mA current passes through a 1.4 cm long solenoid producing a magnetic field of .162 G. How many turns are in the solenoid
Answer:
The number of turns is 64449395
Explanation:
The expression for the solenoid formula is stated below, and it is what we are going to use to solve for the number of turns
B= μ₀nl
where B= magnetic field
μ₀= permeability , 4π × 10⁻⁷ Henry
n= number of turns
l= length of coil
Given data
current I= 2 mA
length L= 1.4 cm to meter we have 0.014
magnetic field B= 0.162 T
From the expression we can make n subject of formula we have
n=B/μ₀l
Substituting we have
n= 0.162/4π × 10⁻⁷*2*10^-3
n= 0.162/8π × 10^⁻10
n= 0.162/2.5136*10^-9
n= 64449395
A pure copper sphere has a radius of 0.935 in. How many copper atoms does it contain? [The volume of a sphere is (4>3)pr3 and the density of copper is 8.96 g>cm3.]
Answer:
47.68 x 10²³ or 4.768 x 10²⁴ copper atoms
Explanation:
Given:
Radius of the copper sphere (r) = 0.935 in
First convert the radius from inches to centimeters
1 in = 2.54cm
0.935in = 0.935 x 2.54cm = 2.3749cm
∴ r = 2.3749cm
Calculate the volume of the copper sphere as follows
Volume = [tex]\frac{4}{3}\pi r^{3}[/tex] [substitute r = 2.3749cm and π = 22 / 7]
Volume = [tex]\frac{4}{3}(\frac{22}{7} ) (2.3749)^{3}[/tex]
Volume = 56.108cm³
From the volume and given density, calculate the mass of the copper sphere
mass = density x volume [density = 8.96g/cm³]
mass = 8.96 x 56.108 = 502.73g
From known facts
1 mole of copper = 63.5g of copper = 6.022 x 10²³ copper atoms.
Then,
502.73 g of copper = [tex]\frac{502.73 * 6.022*10^{23}}{63.5}[/tex] = 47.68 x 10²³ copper atoms
Therefore, the sphere contains 47.68 x 10²³ copper atoms
Answer:
=4.8*10^-24atoms
Explanation:
To find volume of a sphere
= 5.61*10^-5m³ x 8.96gx 100³m³
=502.7g
So we use density of copper to convert volume to mass so
1atm of cux( 1mol of cu/6.02Eatm of cu)*(63.54g of cu/1 mole of cu)
So = 1.055*10-22g cu
So
= 502.7/1.055*10-22g cu
=4.8*10^-24atoms
A well with vertical sides and water at the bottom resonates at 5.63 Hz and at no lower frequency. (The air-filled portion of the well acts as a tube with one closed end and one open end.) The air in the well has a density of 1.10 kg/m3 and a bulk modulus of 1.33 × 10^5 Pa. How far down in the well is the water surface?
Answer:
The value is s = 15.4 \ m
Explanation:
From the question we are told that
The frequency is [tex]f = 5.63 \ Hz[/tex]
The density of air in the well is [tex]\sigma = 1.33 *10^{5} \ Pa[/tex]
The Bulk modulus is [tex]B = 1.33*10^{ 5} \ Pa[/tex]
Generally the distance of the water surface from the opening is mathematically represented as
[tex]s = \frac{1}{4 f } * \sqrt{\frac{B}{\rho } }[/tex]
=> [tex]s = \frac{1}{ 4 * (5.63 )} \sqrt{\frac{1.33*10^{5}}{ 1.10} }[/tex]
=> [tex]s = 15.4 \ m[/tex]
You wish to produce an emf of 41.0 mV using an inductor whose inductance is 13.0 H. You start with a current of 1.50 mA through the inductor and increase the current at a steady rate. What is the current through the inductor at the end of 2.60 s
Answer:
The current through the inductor at the end of 2.60s is 9.7 mA.
Explanation:
Given;
emf of the inductor, V = 41.0 mV
inductance of the inductor, L = 13 H
initial current in the inductor, I₀ = 1.5 mA
change in time, Δt = 2.6 s
The emf of the inductor is given by;
[tex]V = L\frac{di}{dt} \\\\V = \frac{L(I_1-I_o)}{dt} \\\\L(I_1-I_o) = V*dt\\\\I_1-I_o = \frac{V*dt}{L}\\\\I_1 = \frac{V*dt}{L} + I_o\\\\I_1 = \frac{41*10^{-3}*2.6}{13} +1.5*10^{-3}\\\\I_1 = 8.2*10^{-3} + 1.5*10^{-3}\\\\I_1 = 9.7 *10^{-3} \ A\\\\ I_1 = 9.7 \ mA[/tex]
Therefore, the current through the inductor at the end of 2.60 s is 9.7 mA.
Some species of whales can dive to depths of 1 kilometer. What is the absolute pressure they 352 experience at this depth
Answer:
The whales experience pressures of about 9.87Mpa at this depth of 1km into the water.
Explanation:
The absolute pressure can be calculated using the formula: P Abs = P Guage + P Fluid.
This means that once the whales dive under the water, both the pressure from the atmosphere and the pressure from the water is acting on them.
The Guage pressure is 101325 Pa. This can be obtained from standard tables.
The fluid pressure at a depth of 1km (1000 m) can be obtained using the formula: [tex]P = \rho gh[/tex]
Where [tex]\rho[/tex] = density of water = 997 kg/m³
g = acceleration due to gravity = 9.8 m/s2
h = depth of dive = 1000m
[tex]P = 997 \times 9.8 \times 1000 = 9770600 Pa[/tex]
Therefore, Absolute pressure = 101325 Pa + 9770600 Pa = 9871925 Pa
The whales experience pressures of about 9.87Mpa at this depth of 1km
A driver has a reaction time of 0.50 s , and the maximum deceleration of her car is 6.0 m/s² . She is driving at 20 m/s when suddenly she sees an obstacle in the road 50 m in front of her.
What is the distance she passes after noticing the obstacle before fully stopping?
Answer:
43.3 m
Explanation:
given :
the initial velocity of the car , u = 20m/s
The reaction time is 0.5s
the distance that the car will travel during the reaction time
= initial velocity x reaction time
= 20 m/s x 0.5 s
= 10 m
Now we turn our attention to the stopping distance AFTER she reacts and steps on the brakes:
recall that one of the forms that the equations of motions can be expressed is:
v² = u² + 2as
where v = final velocity = 0 because the car comes to a stop
u = initial velocity = 20m/s
a = acceleration = -6.0 m/s² (note negative sign because it is a deceleration)
s = distance traveled (we are asked to find this)
substituting the known values into the equation:
v² = u² + 2as
0² = 20² + 2(-6.0) s
0 = 400 - 12s
1.2s = 400
s = 400/12
s = 33.33 m
Total distance travelled
= distance during reacting time + distance while decelerating
= 10 + 33.3
= 43.3 m
Answer:
43.3 m
Explanation:
Given :
Reaction time = 0.5 sDeceleration = -6.0 m/s²Speed = 20 m/sObstacle Distance = 50 mDistance Travelled during Reaction Period
S = utS = 20 × 0.5S = 10 mUsing the formula v² - u² = 2aS :
Rearrange it so it is equal to 'S'S = v² - u² / 2aS = 0² - 20² / 2(-6) [v = 0, because speed is 0 when car stops]S = -400/-12S = 100/3 = 33.3 mDistance travelled after fully stopping :
10 m + 33.3 m43.3 m