Question

1. The concept of work is equivalent to a transfer of energy.

True

False

2. Work is required to transfer energy from one form to another, for example, to convert kinetic energy into potential energy.

True

False

3. An object with mass of 1000 kg is moving at a rate of 20 m/s. Its kinetic energy is

a. 0 J

b. 20,000 J

c. 200,000 J

d. 400,000 J

4. A car speeds up from 10 m/s to 15 m/s. After some time, it speeds up by another 5 m/s to a speed of 20 m/s. The amount of work in speeding up from 10 m/s to 15 m/s is the same as the work required to speed up from 15 m/s to 20 m/s.

True

False

5. An object is lowered from a height of 10 m to 2 m. In this process, the object is gaining gravitational potential energy.

True

False

6. An object with a mass of 5 kg t is raised from a height of 2 m to 10 m. How much potential energy did the object gain?

a. 40 J

b. 100 J

c. 400 J

d. 500 J

7. An object at rest is dropped from a 30 m tall tower. How fast is the object moving right before impact with the ground?

a. 8 m/s

b. 16 m/s

c. 24 m/s

d. 32 m/s

8. A bullet with a mass of 7.45 g is fired horizontally into a piece of wood. The initial speed of the bullet is 360 m/s. After coming to a complete stop, how much energy was transferred from the bullet?

a. 483 J

b. 10,400 J

c. 54,000 J

d. 483,000 J

Answer #1

1) If a person holds 50 kg object at a height of 2 m above the
floor for 10 s. How much work is done? W = F×d
(2) The work done in lifting 30kg of bricks to a height of 20m
is W = m ×g × d (Formula, W = F × d but Force = m × g)
(3) A total of 4900 J is used to lift a 50-kg mass. The mass is
raised to a...

True or False:
The force in work is the magnitude of the constant force.
T________ F______
When pulling a chest across the floor with a rope tied to the
end, the work increases as the angle decreases towards the
horizontal plane of the floor. T_______ F________
The less the displacement of the apple when pushed across the
desk, the less work that is done. T_____F_____
The work to push the same chair across a surface of 10 m in
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Question 1 (1 point)
Which is not necessary in order to do work on an object (use the
scientific definition of work)?
Question 1 options:
There must be a change in momentum.
A net force must be applied to the object.
The object must undergo a displacement.
A component of the force must be in the direction of motion.
Question 2 (1 point)
The change in gravitational potential energy for a 1.9 kg box
lifted 2.2 m is:
Question 2...

Q1.Energy is defined as
the ability to do work.
the conservation of displacement.
the distance traveled divided by time.
the time rate of doing work.
Q2.While rearranging a dorm room, a student does 300 J
of work in moving a desk 2.0 m. What was the magnitude of the
applied horizontal force?
150 N
600 N
0 N
2940 N
Q3.Power
is force divided by time.
is work divided by time.
is work times time.
has the same units as...

A. Suppose a 10kg object as a total energy of 500J. If all of
this energy is kinetic energy, how fast is the object moving? (I
got 10 m/s) Is this correct?
B. Assume now that the same object has only gravitational
potential energy. If the object is on Earth, how high up is it? (I
got 5.1 m, is this correct?)
C. According to conservation of energy, the object must have the
same TOTAL energy (kinetic plus potential) at...

I already have parts A through D, so no need to work those out
again. Just need E through P. Thanks.
Three small balls of mass 3.7 kg, 2.4 kg, and 3 kg are connected
by light rods laying along the y-axis. The rod connecting the first
and second balls is 4.8 m long and the rod connecting the second
and third balls is 1.9 m. The entire system rotates around the
x-axis, which is between the first and second...

Which of the following statements are true?
True False The proper time interval for an event depends
upon the speed of the observer.
True False The proper length of a meter stick is always
one meter.
True False Relativistic effects become important in our
calculations (for example, more than a 1% effect) only when speeds
are close to the speed of light in vacuum.
True False The total kinetic energy of a body is
limited, since its speed can never exceed 'c'.
True False The...

Questions (use complete sentences)
1) What is a conservation law? What is the basic approach taken
when using a conservation law?
2) Could the linear momentum of a turtle be greater than the
linear momentum of a horse? Explain.
3) Carts A and B stick together whenever they collide. The mass
of A is twice that of B. How could you roll the carts so that they
would be stopped after a collision?
4) How can a satellite’s speed decrease...

1. Which has the greater kinetic energy, a heavy truck at rest
or a moving roller skate?
a. none of above
b. heavy truck at rest
c. the roller skate at rest
d. The kinetic energies are equal.
2. If a sports car with a mass of 2000 kg travels down the road
with a speed of 10 m/s, its kinetic energy is _______________ kg
(m/s)2
a. 80000
b. 16000
c. 8000
d. 100000
e.none of above
3. A sports...

True/False
1. An object is fired from a cannon along a horizontal range.
There are two angles which have the same range.
2. A mass is observed moving to the east at 20 m/s. Some time
later it is moving north at the same speed. Did some external force
act on the mass?
3. An object is fired from the edge of a high cliff at a 45°
angle. Is the range equation useful for finding where the object
hits...

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