Question

Select True or False for each statement.

1 Work cannot be done in the absence of motion.

2 Work is done when the form of energy changes.

3 Without friction or work by an external force, the sum of the
potential and kinetic energies of a body is constant.

4 Energy conservation law for a projectile (no friction): Potential
energy increase equals the kinetic energy decrease.

5. A source of energy is required to do work.

6. More power is required while slowly lifting a box than while
lifting it up quickly.

Answer #1

1. True

Work done = F.d

if there is no motion then d (displacement ) will be zero so work done = 0

2. True ( work - enetgy relation)

3. False

work done by internal force can change its energy .

E.g - When bomb blasts in parts.

4. True.

from work - energ theorem.

work done by gravity = change in K.E.

increase in potential energy ( means negative work done by gravity ) = loss in K.E.

5. True

from work - energy theorem.

work done = change in energy

6. False

Power = work / time

same work done quickly, then time will be less .

ao powerr will be more.

power is less in slowly lifting.

Learning Goal:
To understand how to apply the law of conservation of energy to
situations with and without nonconservative forces acting.
The law of conservation of energy states the following:
In an isolated system the total energy remains constant.
If the objects within the system interact through gravitational
and elastic forces only, then the total mechanical energy
is conserved.
The mechanical energy of a system is defined as the sum of
kinetic energy K and potential energy
U. For such...

8 through 10 done please!!
3.13.6
Question 110 pts
A 319 kg motorcycle is parked in a parking garage. If the car has
35,494 J of potential energy, how many meters above ground is the
car? Report your answer to 1 decimal place. Please do not include
units or the answer will be marked incorrect.
Flag this Question
Question 210 pts
A box sitting on the top of a hill has 252 J of potential energy.
If the hill is...

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...

Finding the Spring Constant
We can describe an oscillating mass in terms of its position,
velocity, and acceleration as a function of time. We can also
describe the system from an energy perspective. In this experiment,
you will measure the position and velocity as a function of time
for an oscillating mass and spring system, and from those data,
plot the kinetic and potential energies of the system.
Energy is present in three forms for the mass and spring system....

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...

do all five questions
Question 1
20 pts
Ignoring the effects of air resistance, if a ball falls freely
toward the ground, its total mechanical energy
Group of answer choices
increases
remains the same
not enough information
decreases
Flag this Question
Question 2
20 pts
A child jumps off a wall from an initial height of 16.4 m and lands
on a trampoline. Before the child springs back up into the air the
trampoline compresses 1.8 meters. The spring constant...

just do questions 5 through 10
3.13.6
Question 110 pts
A 319 kg motorcycle is parked in a parking garage. If the car has
35,494 J of potential energy, how many meters above ground is the
car? Report your answer to 1 decimal place. Please do not include
units or the answer will be marked incorrect.
Flag this Question
Question 210 pts
A box sitting on the top of a hill has 252 J of potential energy.
If the hill...

answer all questions
3.13.6
Question 110 pts
A 319 kg motorcycle is parked in a parking garage. If the car has
35,494 J of potential energy, how many meters above ground is the
car? Report your answer to 1 decimal place. Please do not include
units or the answer will be marked incorrect.
Flag this Question
Question 210 pts
A box sitting on the top of a hill has 252 J of potential energy.
If the hill is 279 meters...

Two boxes are stacked, with box B placed on top of box A. If box
A is pushed such that both boxes move with a decreasing speed, is
there any friction on either box?
(a) Kinetic friction on box A and no friction on box B (b)
Kinetic friction on box A and static friction on box B
(c) Kinetic friction on box A and kinetic friction on box B (d)
Static friction on box A and kinetic friction on...

A grey body is one whose absorptivity
1. does not vary with temperature and wavelength of the incident
ray
2. is equal to its emissivity
3. varies with temperature
4. varies with wavelength of the incident ray
A liquid is in equilibrium with its vapor at its boiling point.
On an average, the molecules in the liquid and gaseous phases have
equal
1. potential energy.
2. kinetic energy.
3.temperature. 4. intermolecular forces of attraction.
A liquid of density 1000 kg/m3...

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