Answer:
The time taken by the car is 8.94 seconds.
Its velocity changes at different time intervals. Calculate the instantaneous
velocity at time 3 sec. The distance is given by equation 2t² – 4t
Answer:
The instantaneous velocity at time 3 sec is 8 (no units specified).
Explanation:
Instantaneous Velocity
The instantaneous velocity of an object is the derivative of the distance function with respect to time.
The distance is given by the function:
[tex]x(t)=2t^2 - 4t[/tex]
Now we compute the instantaneous velocity function by taking the derivative of x:
[tex]\displaystyle v(t) = \frac{dx}{dt}[/tex]
[tex]\displaystyle v(t) = \frac{d(2t^2 - 4t)}{dt}[/tex]
[tex]v(t) =4t -4[/tex]
Now evaluate the velocity for t=3 sec:
[tex]v(3) =4(3) -4[/tex]
[tex]v(3) =12 -4 = 8[/tex]
The instantaneous velocity at time 3 sec is 8 (no units specified).
Rita wants to make some toast for breakfast, which she knows involves a chemical change to the bread.
She puts a slice of bread in the toaster, but, after 10 minutes, she notices that the sides of the bread are
black. What caused this chemical change to go too far?
A. an increase in temperature
B. a decrease in temperature
C. the size of the bread
D. the type of bread
Answer:
A
Explanation:
The toaster was too high so its the increase in eat
A student builds an electromagnet using a battery, an iron nail, and some insulated wire. The wire is wrapped around the nail 50 times, then connected to the
battery. What changes could the student make to increase the strength of the electromagnet?
1. wrap more wire around the nail
2. increase the voltage of the battery
3. use a switch to turn the electromagnetic on and off
4. increase the size of the nail
A. 1 and 2
B. 2 and 4
C. 1,2 and 4
D. 1,2,and 3
Answer:
a
Explanation:
its right
To increase the electromagnet's strength, the student must enlarge the nail, wrap more wire around the nail, and increase the voltage of the battery. Option c is the correct answer.
How does an electromagnet work?The mechanics of an electromagnet are not overly complicated. It is accomplished by wrapping a length of conductive wire, usually copper, around a metal object.Until electricity is introduced, this appears to be nothing more than a jumbled collection of parts, similar to Frankenstein's monster. An electromagnet, on the other hand, does not require a storm to be activated. A current is introduced and flows through the wire, which can come from a battery or another source of power.As a result of the magnetic field created around the coiled wire, the metal is magnetized as if it were a permanent magnet. Electromagnets are useful because they can be activated and deactivated by closing and opening a circuit.To learn more about electromagnet, refer to
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Please answer ASAP, and please don't joke around and actually do answer my question. I will give you brainliest if you answer it well:
A girl, standing on a bridge, throws a stone vertically downward with an initial velocity of 12.0 m/s, into the river below. If the stone hits the water 2.50 seconds later, what is the height of the bridge above the water?
Remember to identify all your data, write the equation, and show your work.
Answer:
30 feet
Explanation:
First off, if they are throwing at 12.0 m/s and it takes 2.5 seconds. It will be the act of multiplication.
12 times 2.5 is 30, because 12 times 2 is 24 plus 12 divided by 2 which is 6 so 24 plus 6 is 30.
Which of these is a base?
HNO3
vinegar
ammonia
HCl
The correct answer is Ammonia
what energy transfer will a stretched rubber band have when let go
Answer:
when the rubber band is realeased the potential energy is quickly converted to kinetic energy this is equal to one mass of the the rubber band multiplied by its velocity( in meters per second)
In an experiment, a research collected the following informationabout a solution made from a certain
food. What can we conclude about the food?
• pH = 3.0
• Taste = Sour
A. Acid
B. Base
C. Neutral
D. Salt
Answer:
salt
Explanation:
Q17: The coefficient of linear expansion of steel is a = 11 x 10-6 / °C. A steel
ball has a volume of exactly 100 cm3 at 0°C. When heated to 100°C, its
volume becomes in (cm3):
A
B
D
E
100.33
100.11
100.0011
100.0033
None of them
Solution:
The coefficient of volume expansion
p = ΔV/V1Δt
3a = V2-V1/V1Δt
Given
a = = 11 x 10-6 / °C
V2 is the final volume
V1 is the initial volume = 100cm³
Δt = 100-0 = 100°C
Substitute
3(11 x 10-6) = V2-100/100(100)
33*10^-6 * 10000 = V2-100
33*10^-2 = V2-100
V2 = 100 + 0.33
V2 = 100.33
Hence the new volume is 100.33cm³
A 300 g object attached to a horizontal spring moves in simple harmonic motion with a period of 0.340 s. The total mechanical energy of the spring–object system is 3.00 J.
(a) What is the spring constant (in N/m)?
(b) What is the amplitude (in m) of the motion?
(c) What is the percentage change in amplitude of motion if the total energy of the system is increased to 5.00 J?
Answer:
Explanation:
angular velocity ω = 2π / T where T is time period of rotation .
= 2 x 3.14 / .34 = 18.47 rad /s
Total mechanical energy = 1/2 m ω²Α² where A is amplitude .
spring constant = k
[tex]\omega=\sqrt{\frac{k}{m} }[/tex]
m is mass
[tex]\omega^2=\frac{k}{m} }[/tex]
18.47² = k / .3
k = 102.34 N /m
b )
energy = 1/2 m ω²Α²
3 = .5 x 18.47² x A²
A² = .01759
A = .1326
13.26 cm .
c )
If energy becomes 5 J
5 = .5 x 18.47² x A²
A² = .0293
A = .1711
= 17.11 cm
percent increase
= (17.11 - 13.26 )x100 / 13.26
= 29%
A pendulum is transported from sea-level, where the acceleration due to gravity g is 9.80 m/s2, to the bottom of Death Valley. At this location, the period of the pendulum is decreased by 3.00%. What is the value of g in Death Valley
Answer: the value of g in Death Valley is 10.417 m/s²
Explanation:
Given that;
acceleration due to gravity at the point is g = 9.8 m/s²
Lets say the acceleration due to gravity at the bottom of Death valley is g'
as the period of the pendulum is decreased by 3.00%
T' = 0.97 T
T is the period of the pendulum at sea level and T' is the period of the pendulum at bottom of Death valley
therefore from the relation
T = 2π√(l/g)
g'/g = T²/T'²
g' = (T²/ (0.97T)²)g
g' = 1.063g
g' = 10.417 m/s²
therefore the value of g in Death Valley is 10.417 m/s²
A child sits on a merry-go-round, 1.5 meters from the center. The merry-go-round is turning at a constant rate, and the child is observed to have a radial acceleration of 2.3 m/s2. How long does it take for the merry-go-round to make one revolution
Answer:
5 .07 s .
Explanation:
The child will move on a circle of radius r
r = 1.5 m
Let the velocity of rotation = v
radial acceleration = v² / r
v² / r = 2.3
v² = 2.3 r = 2.3 x 1.5
= 3.45
v = 1.857 m /s
Time of revolution = 2π r / v
= 2 x 3.14 x 1.5 / 1.857
= 5 .07 s .
The merry-go round will take 5.07 s to complete one complete revolution.
Given data:
The distance of child from the center is, r = 1.5 m.
The magnitude of radial acceleration is, [tex]a = 2.3 \;\rm m/s^{2}[/tex].
Since, the child is on merry-go round, which is undergoing a rotational motion. And radial acceleration means that it is under the acceleration, whose value is given as,
[tex]a=\dfrac{v^{2}}{r}\\\\v=\sqrt{a \times r}[/tex]
Here, v is the linear velocity.
Solving as,
[tex]v=\sqrt{2.3 \times 1.5} \\\\v=1.857 \;\rm m/s[/tex]
Now, we to obtain the time taken by merry-go round to complete one revolution. Then the expression for the time taken to complete one revolution is,
[tex]T=\dfrac{2 \pi r}{v}\\\\T=\dfrac{2 \pi \times 1.5}{1.857}\\\\T = 5.07 \;\rm s[/tex]
Thus, we can conclude that the merry-go round will take 5.07 s to complete one revolution.
Learn more about the centripetal acceleration here:
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it is not uncommon for us to hold stereotypes toward people. The main advantage of forming a stereotype is that it______. The main disadvantage is that it_____.
Answer:
It is not a me mental shortcut
Explanation:
Can be changed easily
It is not uncommon for us to hold stereotypes toward people. The main advantage of forming a stereotype is that they make fast and quick decision. The main disadvantage is that they make generalized decision.
Who is a stereotype person?A stereotype is a persistent, vastly oversimplified view about a particular group or category possesses. A stereotype person make his own belief for the peoples.
A stereotype has the advantage of allowing us to respond quickly to events, since we may have had a similar experience before.
One negative is that it causes us to overlook individual distinctions, leading us to believe things about others that are not always true.
It is not uncommon for us to hold stereotypes toward people. The main advantage of forming a stereotype is that they make fast and quick decision. The main disadvantage is that they make generalized decision
The correct option for the blanks are make fast and quick decision and generalized decision.
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A horizontal force of 100 N is applied to move a 50-kg cart (initially at rest) across a 10 m level surface. What is the final kinetic energy of the cart?
The net force on the cart is 100 N in the direction of its motion, so by Newton's second law we can find the acceleration a applied to it:
100 N = (50 kg) a
a = (100 N) / (50 kg)
a = 2 m/s²
The cart starts at rest and travels a distance of 10 m, so that its final velocity v satisfies
v ² - 0² = 2 (2 m/s²) (10 m)
v ²= 40 m²/s²
and so the cart ends up with kinetic energy
KE = 1/2 m v ² = 1/2 (50 kg) (40 m²/s²) = 1000 J
Can you help me with this question please
Answer:
9.6 Ω
Explanation:
Notice that this circuit is the same as the one shown in the attached image.
Then we calculate the parallel of R1 and R3 first:
Since R1 = 30 Ω and R2 = 20 Ω, the parallel equivalent of this is 12 Ω and this in series with R5 (4 Ω) is 16 Ω.
Now we calculate the parallel circuit of the three resistors
40 Ω, 60 Ω, and 16 Ω, which gives us: 9.6 Ω
1. A person weighs 155 lbs and is walking 3.1 miles per hour. How much kinetic energy does the person have? (Keep in mind, 1 kg is 2.2 lb, and 1 m/s is 2.24 mi/h.)2. What is the kinetic energy of a 5 g bullet travelling 400 m/s?
3. Is it possible to have a negative KE? Why or why not?
Answer:
Explanation:
Kinetic energy is expressed as;
KE =1/2 mv²
M is the mass
v is the velocity of the object
1) Given
Mass = 155lb
Velocity = 3.1mi/hr
Since 1kg = 2.2lb
x = 155lb
x= 155/2.2
x = 70.45kg
Also
1m/s = 2.24mi/hr
y = 3.1mi/hr
y = 3.1/2.24
y = 1.384m/s
KE = 1/2(70.45)(1.384)²
KE = 0.9577×70.45
KE = 67.47Joules
2) M = 5g =0.005kg
V = 400m/s
KE = 1/2(0.005)400²
KE = 80000×0.005
KE = 400Joules
3} Since a body decelerates (negative acceleration) this mean that the velocity of a body can be a negative value showing that it is possible for a moving body to possess negative kinetic energy.
Left Force
150N
50N Right Force
Calculate the net force acting on the object. Show your work and be sure to
clude the correct unit.
Answer:
100 N to the left
Explanation:
Left force:150 N
Right force:50 N
So 150 - 50 = 100 N
Since the left force is greater, the resultant force is to the left
Impact extinction 65 million years ago over 50% of all species became extinct, ending the reign of dinosaurs and opening the way for mammals to become the dominant land vertebrates. A theory for this extinction, with considerable supporting evidence, is that a 10-km-wide 1.8×1015kg asteroid traveling at speed 11 km/s crashed into Earth.
A) Determine the change in velocity of Earth due to the impact. Mass of Earth is 5.98×1024kg.
B) Determine the average force that Earth exerted on the asteroid while stopping it. Assume that stopping distance is 0.60 km (depth of the crater created)
C) Determine the internal energy produced by the collision (a bar chart for the process might help). By comparison, the atomic bombs dropped on Japan during World War II were each equivalent to 15,000 tons of TNT (1 ton of TNT releases 4.2×109J of energy).
Answer:
for a)
Explanation:
(1.8 x 10^15)(11 x 10^3 m/s) = (5.98 x 10^24 + 1.8 x 10^15)vf
vf= (1.8 x 10^15)(11 x 10^3 m/s) / (5.98 x 10^24 + 1.8 x 10^15)
= 3.3×10−6 m/s
which two conditions would result in the strongest electric force between charged objects
Answer:
A and B
Explanation:
The two conditions which results in the strongest electric force between charged objects are when they close together secondly, when the objects are conductors with balanced charges.
What is electric force ?Electric force is the force generated between charged bodies. There are both repulsive and attractive electric forces. Like charges exerts a force of repulson between each other. Unlike charges will exert an attractive force between each other.
According to Coulomb's law of electric forces is directly proportional to the magnitude of charges and inversely proportional to the distance between them. Thus , when the objects are closer the greater force is exerted between them.
Insulators does not allow flow of free electrons and the electric force between them is weak. Whereas, when two conductors of unlike charges exerts strong electrostatic force of attraction. Hence, option B and C are correct.
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When are zeros significant when found in front of (to the left) of the decimal point?
Answer:
If a zero is found between important digits, it is important. Zeros are also used as (not salient) holders to the left of digits if the number is in fact a decimal. Example from www.rpi.edu: , a mass of 42 g has two significant digits. Expressed in kilograms, the mass of 0.042kg should still have two significant digits.
Explanation:
Zeros are also used as (not salient) holders to the left of digits if the number is in fact a decimal. Example from www.rpi.edu: "A mass of 42 g has two significant digits. Expressed in kilograms, the mass of 0.042kg should still have two significant digits."
Hope this comes in handy, have a great day!
A jogger runs 4 km in 0.4 hr, then 8 km in 0.8 hr. What is the average speed of the jogger?
The jogger would have ran about 10 km/h.
Is a compound considered a pure substance?
Answer:
It depends on which compound you use carbon dioxide can be while helium will not but if you where to sum it up it would be use because simply most compounds are considered pure substance.
Explanation:
A 2,000 kg car travels with a tangential
velocity of 12 m/s around a circular
track with a radius of 30 meters. What
is the car's rate of centripetal
acceleration?
The car's rate of centripetal acceleration in the circular path is 4.8 m/s².
The given parameters;
mass of the car, m = 2,000 kgvelocity of the car, v = 12 m/sradius of the circular path, r = 30 mThe centripetal acceleration of the car is calculated as follows;
[tex]a_c = \frac{v^2}{r}[/tex]
where;
v is the tangential speed of the carr is the radius of the circular pathSubstitute the given parameters and solve for the centripetal acceleration;
[tex]a_c = \frac{12^2}{30} \\\\a_c = 4.8 \ m/s^2[/tex]
Thus, the car's rate of centripetal acceleration is 4.8 m/s².
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Someone help me please it’s urgent
Which statement correctly describes the diferences between positive and negative acceleration
O Positive acceleration describes a change in speed, negative acceleration desxibes no change in speed,
Positive acceleration describes no change in speed, negative acceleration desibes a change in speed,
Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
O Positive acceleration describes a decrease in speed, negative sideration describes an increase in sarees
Answer:The answer is this Positive acceleration describes an increase in speed, negative sexeleration desnibes a decrease in speed
Explanation:
At what condition does a body becomes weightless at the equator?
Answer:
The decrease is due to the bulge at the equator (putting more distance between the rest of the planet and the surface
Explanation:
An artery with cross sectional area of 1 cm2 branches into 20 smaller arteries each with 0.5 cm2 cross sectional area. If the velocity of blood in the thicker artery is v, what is the velocity of the blood in the thinner arteries
Answer:
The velocity of the blood in the thinner arteries is 0.1 times that of the thicker artery.
Explanation:
To find the velocity of the blood we need to use the continuity equation:
[tex] n_{1}A_{1}v_{1} = n_{2}A_{2}v_{2} [/tex] (1)
Where:
n: is the number of branches
A: is the cross-sectional area
v: is the velocity
For artery 1, we have:
n₁ = 1, A₁ = 1 cm², v₁ = v
For the 20 arteries (2), we have:
n₂ = 20, A₂ = 0.5 cm², v₂ =?
By using equation (1):
[tex] n_{1}A_{1}v_{1} = n_{2}A_{2}v_{2} [/tex]
[tex] 1 cm^{2}*v = 20*0.5 cm^{2}*v_{2} [/tex]
[tex] v_{2} = \frac{1 cm^{2}*v}{20*0.5 cm^{2}} = \frac{v}{10} = 0.1v [/tex]
Therefore, the velocity of the blood in the thinner arteries is 0.1 times that of the thicker artery.
I hope it helps you!
The engine of a boat (m = 2280 kg) exerts an
1800 N force northward, while the current
pushes it 1050 N eastward.
What is the magnitude of the acceleration
of the boat?
Answer:
a = 0.9139 [m/s²]
Explanation:
To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
The forces are on two different axes, x & y axes (North and East). In this way, the Pythagorean theorem should be used to determine the total force.
Fx = 1800 [N]
Fy = 1050 [N]
[tex]F = \sqrt{(F_{x} )^{2} +(F_{y} )^{2} } \\F=\sqrt{(1800)^{2} +(1050)^{2} } \\F=2083[N][/tex]
Now using Newton's second law.
ΣF = m*a
where:
F = force = 2083.8 [N] (units of Newtons)
m = mass = 2280 [Kg]
a = acceleration [m/s²]
2083.8 = 2280*a
a = 0.9139 [m/s²]
When a balloon is rubbed on a surface and then touched to hair it will attract the hair, causing it to stick to the balloon. Explain why this happens.
Answer:
electricity
Explanation:
Answer:
This is called static electricity
Explanation:
The reasoning behind this is because the negative electrons in your hair are being transferred to the balloon, then when the balloon is removed it pulls on the hair with an attractive electric force.
A heavy bank-vault door is opened by the application of a force of 300 N directed perpendicular to the plane of the door at a distance of 0.80 m from the hinges. What is the torque?
Question 4 options:
1.) 120 Nm
2.) 240 Nm
3.) 375 Nm
4.) 300 Nm
Answer:
240Nm
Explanation:
Given parameters:
Force on the bank vault = 300N
Distance to the plane of the vault = 0.8m
Unknown:
Torque = ?
Solution:
Torque is the component of force that causes an object to rotate about an axis;
Torque = Fr x sinФ
Here Ф = 90°
r = distance
Torque = 300 x 0.8 x Sin 90°
Torque = 240Nm
What is the mechanical advantage of a nail puller where you exert a force 45 cm from the pivot and the nail is 1.8 cm on the other side? What minimum force must you exert to apply a force of 1250 N to the nail?
Answer:
Explanation:
Mechanical Advantage is the ratio of the distance of the input load (Li)from the pivot to the output load applied to the pivot(Lo)
MA = Li/Le
Given;
Li = 45cm
Lo = 1.8cm
MA = 45/1.8
MA = 25
Hence the mechanical advantage is 25
Also MA is expressed in terms of the force ratio which is the ratio of the Load to the effort applied.
MA = Load/Effort
Given
Load = 1250N
MA = 25
Effort = ?
Substitute
25 = 1250/Effort
Effort = 1250/25
Effort = 50N
Hence the minimum force exerted on the load is 50N