Answer:
2.1 seconds
Explanation:
let D represent the height in meters
let g represent gravity in meters per second squared
let t represent time in seconds
D= -42 meters (negative because it falls down)
g= -9.8m/s^2
t= [tex]\frac{-42 meters}{9.8 m/s^2}[/tex]
this gives t= 4.2857 s^2
the meter units cancel out in the division
now we must simplify the units to singular seconds so...
[tex]\sqrt{4.3 s^{2} }[/tex] which simplifies to [tex]\sqrt{4.3}[/tex] x [tex]\sqrt{s^{2} }[/tex]
this equals 2.1 seconds
1. How much energy is needed just to melt 0.56kg of ice at 0◦ C?
2. How much energy is needed just to boil 5kg of water at 100◦ C?
3. What is the specific heat of metal if its mass is 27 g and it requires 420 J of heat energy to
increase its temperature from 25°C to 50°C?
please help me out I dont have much time
Answer:
This will require 266.9 of heat energy.
Explanation:
To calculate the energy required to raise the temperature of any given substance, here's what you require:The mass of the material, m The temperature change that occurs, ΔT The specific heat capacity of the material,
c
(which you can look up). This is the amount of heat required to raise 1 gram of that substance by 1°C.
Here is a source of values of
c for different substances:
Once you have all that, this is the equation:
Q=m×c×ΔT(Q is usually used to symbolize that heat required in a case like this.)For water, the value of c is 4.186g°C So, Q=750×4.186×85=266=858=266.858
Explain why the formation of sand is a physical change.
Answer:
The formation of sand is a physical change because some of the physical properties of the rocks change, but their identities do not. The particles of rock are rearranged as their sizes and shapes change, but their identities and total mass remain the same.
pls help quickly
Which of these materials best scatters the light that strikes it?
a pure water
b shiny mirror
c frosted glass
d eyeglass lens
Answer: frosted glass
Explanation:
Answer:
C
Explanation:
Frosted Glass
A 2.6 kg mass attached to a light string rotates on a horizontal,
frictionless table. The radius of the circle is 0.525 m, and the
string can support a mass of 17.9 kg before breaking. The
acceleration of gravity is 9.8m/s2. What maximum speed can
the mass have before the string breaks?
The maximum speed the mass can have before it breaks is 2.27 m/s.
The given parameters:
maximum mass the string can support before breaking, m = 17.9 kgradius of the circle, r = 0.525 mThe maximum speed the mass can have before it breaks is calculated as follows;
[tex]T = ma_c\\\\Mg = \frac{Mv^2}{r} \\\\v^2 = rg\\\\v = \sqrt{rg} \\\\v_{max} = \sqrt{0.525 \times 9.8} \\\\v_{max} = 2.27 \ m/s[/tex]
Thus, the maximum speed the mass can have before it breaks is 2.27 m/s.
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what is the velocity of 8.01
Answer: The velocity of what?
A medieval instrument used to determine the position of the sun:
Answer: astrolabe
Explanation:
A 40 N block is resting on a rough inclined plane. The static friction between the block and the plane is ____ N.
The static friction between the block and the plane is [tex]40(\mu_s) \ N[/tex].
The given parameters:
Weight of the block, W = 40 NThe normal reaction on the rough surface due to weight of the block is calculated as follows;
[tex]F_n = 40 \ N[/tex]
The static friction between the block and the plane is calculated as follows;
[tex]F_s = \mu_s F_n[/tex]
where;
[tex]\mu_s[/tex] is coefficient of static frictionThus, the static friction between the block and the plane is [tex]40(\mu_s) \ N[/tex].
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If there were no dark energy in the universe, the value of __________ would solely determine the evolution and fate of the universe.
Answer:
Ωmass
Explanation:
If there were no dark energy in the universe, the value of Ωmass would determine the evolution and fate of the universe.
An object is dropped from a building and strikes the ground with a speed of 52 m/s. How tall is the building?
Answer:
5.3 0 meter is the hight of the building is it
A firecracker is placed in the middle of a room. When the firecracker explodes the parts of the firecracker scatter in all different directions. The total combined momentum of all the parts of the firecracker added together after the explosion must be
A.
more than before the explosion.
B.
less than before the explosion.
C.
can not tell from the given information
D.
the same as before the explosion.
Because momentum is a vector quantity, the total combined momentum of all the parts of the firecracker added together after the explosion must be the same as before the explosion. The correct answer is D
Given that a firecracker is placed in the middle of a room. This means that the firecracker is at rest. That is its momentum is equal to zero. When the firecracker is lit up, it will move in a certain velocity before it explodes. Since the total combined momentum of all the parts of the firecracker scatter in all different directions are considered, that is added up, then momentum will always be conserved. That is,
The momentum of an object before explosion will always be equal to the momentum of the object after explosion.
Because momentum is a vector quantity, in which we must consider it magnitude and direction, the best answer to this question is option D.
That is,
The total combined momentum of all the parts of the firecracker added together after the explosion must be the same as before the explosion
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A train starts at rest and ends up with 1500 J of kinetic energy. How much work was done on the train?
Answer:
1500 J
Explanation:
Apparently, we're to assume that no energy is lost to friction or other effects. Then all of the energy the train has is due to work being done on it.
1500 J of work was done on the train
A woman of mass 49 kg jumps off the bow
of a 78 kg canoe that is intially at rest.
If her velocity is 4.5 m/s to the right, what
is the velocity of the canoe after she jumps?
Answer in units of m/s i.
x x
The woman-canoe system has zero initial momentum. When the woman jumps from the canoe, the total momenta of the woman and canoe is conserved, so that
0 = (49 kg) (4.5 m/s) + (78 kg) v
where v is the velocity of the canoe. Solving for v, we find
(78 kg) v = - (49 kg) (4.5 m/s)
v = - 49/78 (4.5 m/s)
v ≈ -2.8 m/s
which is to say, the boat is given a velocity of 2.8 m/s to the left.
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(answer choices: applied force, normal force, friction, electrical force, magnetic force and gravitational force)
(question in picture)
Answer:
3
Explanation:
because they are pushing a body
The body weighs 15N. What is the mass of that body?
A car travels 120 miles in 12 hours. What is
the car's speed?
Select one:
O a. 10 m/s
b. 10 mph
c. 1200 mph
O d. 0.1 m/s
Answer:
I hope it will help you...
#CARRYONLERANING
mrs. knight drops her briefcase. when the briefcase lands on the floor, what is the reaction force to the action force of the briefcase on the floor?
Answer:
The force of the floor on the briefcase
Explanation:
The briefcase hits the floor and stops the falling which is reacting to the briefcase that was falling and hits the floor.
The falling briefcase would be the action force because it is moving downward
and
The reaction force would be the floor because it will react on the briefcase.
Hope this Helps
When the briefcase lands on the floor, the reaction force to the action force of the briefcase on the floor is force of the floor on the briefcase.
What are action force and reaction force?
It might be difficult to distinguish between action and reaction forces. This is due to the fact that both forces are always present.
One might argue that there are an equal number of forces in the universe if one were to count them all. However, the definition of the action force is provided by the perspective of the interaction analysis in order to help the argument.
A force that is applied to an object is known as an action force.
An action force with an opposite direction has an effect called a reaction force.
These two forces—also referred to as action and reaction forces—are covered by Newton's third law of motion.
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#SPJ5
Share your thoughts about this statement by John Wesley
"Electricty is the soul of universe"
Answer:
I think this statement is true at least in modern day times. The world runs on nothing but technology. People use more technology instead of old school textbooks and papers. Imagine living in a world without technology… that means no cars, no trains, no devices, no machines like your stove or printer, no lights and lots more. John Wesley is 100 percent correct with this statement. Electricity is indeed the powerhouse of the universe.
Please help someone. A generator consumes 147 joules of energy in fuel and produces 75 joules of energy
in electricity. Engineers are challenged to produce a generator that is 20% more
efficient. Which of the following combinations of input and output energy represents a generator that has met this design challenge?
a. 150 joules of fuel to produce 90 joules of electricity
b. 135 joules of fuel to produce 68 joules of electricity
c. 60 joules of fuel to produce 100 joules of electricity
d. 115 joules of fuel to produce 82 joules of electricity
Answer:
A
Explanation:
Current effiency
= 75/147
= 0.5102
New Efficiency
= 120/100 × 0.5102
= 0.6122
Only option A satisfies this efficiency.
help will give brainlist
Which unit is used for current?
power
resistance
voltage
amperes
Convert: 12 km/hr =
m/s
[tex]12~ \text{km} ~ \text{h}^{-1} = \dfrac{12 \times 1000}{3600} ~~ \text{m s}^{-1} = 3.33 ~~ \text{m s}^{-1}[/tex]
Answer:
3 1/3 or 3.3333....
Explanation:
You multiply the kilometres by 1,000 because there are 1,000 metres in a kilometre. Then you divide by 60 because there are 60 minutes per hour, and then again by 60 because 60 seconds per minute.
12,000 / 60 = 200
200 / 60 = 3.333
A furniture crate of mass 60 kg is at rest a loading ramp that makes an angle of 25° with the horizontal
The coefficient of kinetic friction between the crate and the ramp is 0.2. What force, applied parallel to the incline, is required to push the crate up the incline at a constant speed?
Answer:
furniture crate of mass 60 kg is at rest a loading ramp that makes an angle of 25° with the horizontal
The coefficient of kinetic friction between the crate and the ramp is 0.2. What force, applied parallel to the incline, is required to push the crate up the incline at a constant speed?
Explanation:
furniture crate of mass 60 kg is at rest a loading ramp that makes an angle of 25° with the horizontal
The coefficient of kinetic friction between the crate and the ramp is 0.2. What force, applied parallel to the incline, is required to push the crate up the incline at a constant speed?
[tex] \huge \boxed{ \sf lol}[/tex]
Name the two sources of light.
Answer:
Natural light (Sun, stars.etc.) and Artificial light (Lamposts, televisions.etc.)
Hope that helps. x
Two boats race in the water. One turns around to head back in the other direction to complete the race, but it collides into the boat that was now directly in front. What forces may have been a part of the collision? Describe them in detail.
The two forces involved in this collision are the colliding force and the reaction force which are equal in magnitude but opposite in direction.
According to Newton's third law, action and reaction are equal and opposite. This law is very important in describing head - on collisions between objects and is particularly apt in describing the collision between the two boats.
In this collision, two forces are important these are the action and the reaction. The action is the colliding force which the boat that was hit experiences. The reaction force is the force that this boat experiences as a result of hitting the boat in front of it. The both forces are equal in magnitude but opposite in direction.
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a -0.06 C charge is placed in a uniform electric field with a strength of 200 N/C. what is the magnitude and direction of the force on the charge
The magnitude and direction of the force on the charge is -12 N opposite the electric field
To calculate the force on a charge in an electric field, we make use of the formula below.
Formula
F = E×Q .......................... Equation 1
Where:
F = Force on the chargeE = Electric FieldQ = chargeFrom the question,
Given:
E = 200 N/CQ = -0.06 CSubstitute these values into equation 1
F = 200(-0.06)F = -12 NNote: The negative sign indicates that the force is in the direction negative of the electric field.
Hence, The magnitude and direction of the force on the charge is -12 N opposite the electric field
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Answer: A edge 202694020
Explanation:
1 point
A hairdryer uses 10 A of current when plugged into a 120 V outlet. How
much power does it use?
Answer:
1200 watt
Explanation:
P= I*V=10*120=1200watt
If an atom has two protons and three electrons, then the atom is-?
A. positively charged.
B. negatively charged.
C. radioactive.
D. neutral.
Hope you could get an idea from here.
Doubt clarification - use comment section.
What is centripetal force and elastic force
Answer:
centripetal force is a net force that acts on an object to keep it moving along a circular path and elastic force acts to return a spring to its natural length
What is the magnitude of the resultant of
a 3.0-
meter displacement and a 4.0-meter
displacement as shown in the diagram?
A. 1.0 meter
4.0 meters
B. 5.0 meters
3.0 meters
C. 7.0 meters
D. 12 meters
Answer:b. 5.0 meters
Explanation: d² = 3²+4²
d² = 9+16
d² = 25
d = √25
d = 5m
The magnitude of the displacement is 5 m as shown in the diagram. Option B is correct.
What is displacement?
Displacement can be defined as the total change in the position of the object. It is a vector quantity.
From the Pythagorean theorem,
[tex]d =\sqrt { 3^2 +4^2}\\\\d = \sqrt {25}\\\\d = 5[/tex]
Therefore, the magnitude of the displacement is 5 m.
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What is the average speed of a car that travels 30 m in the 3 secs and 2 m 4 secs and 20 m 5 secs
Answer:
4.3333333
Explanation:
total distance / total time taken
30 + 2 + 20 / 3 + 4 + 5
52 / 12
4.3 recurring
A projectile is fired with a velocity of 320 ms at an angle of 30 degree to a horizontal.1 Find the time to reach the maximum height. 2 it's horizontal range.
(a) The time taken for the projectile to reach the maximum height is 32.65 s.
(b) The horizontal range of the projectile is 9,049.1 m.
The given parameters:
Initial velocity of the projectile, u = 320 m/sAngle of projection, = 30 degreesThe time taken for the projectile to reach the maximum height is calculated as follows;
[tex]v_f = u- gt\\\\0 = 320 - 9.8t\\\\9.8t = 320\\\\t = \frac{320}{9.8} \\\\t = 32.65 \ s[/tex]
The horizontal range of the projectile is calculated as follows;
[tex]R = \frac{u^2 sin(2\theta)}{g} \\\\R = \frac{320^2 \times sin(2\times 30)}{9.8} \\\\R = 9,049.1 \ m[/tex]
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