Download Work, Power and Energy

Work, Power and Energy
Name___________________
Directions: Use your reference tables or textbooks on the counter to answer the
following questions. This will be collected and graded. You may work together.
I.
Write the formulas for the following and the units for each:
a. Work
b. Power
c. Kinetic Energy
d. Gravitational Potential Energy
e. Elastic Potential Energy
II.
Define the following and give an example to illustrate the concept.
a. Work-Energy Theorem
b. Conservation of Mechanical Energy:
III.
Answer the following questions using the formulas from above:
a. A student lifts a box of books that weighs 185 N, 0.800m. How much
work was done?
b. Two students exert a force of 825 N in pushing a car 35 m. How much
work is done on the car?
c. How much work does the force of gravity do when a 150 kg mass falls
3.5m?
d. A box that weighs 575 N is lifted a distance of 20.0 m straight up a motor
in 10.0s, how much power is developed by the motor?
e. An electric motor develops 65,000 Watts of power as if it lifts a loaded
elevator 17.5 m in 35 s. How much force does the motor exert?
f. A 12,000-Watt (12 kW) motor produces a force of 4,325 Newton’s on a
go ship, what is the ships velocity?
g. A 0.05 kg bullet has a velocity of 200 m/s as it leaves the barrel of a gun,
what is energy the bullet possesses?
h. The energy of car traveling at a speed of 20 m/s is 4.8 x 105 Joules, what is
the mass of the vehicle?
i. How fast would a 6.0 kg bowling ball be traveling if it had 100 J of kinetic
energy?
j. A 120.0kg person is standing on a cliff that is 150.0 m high, how much
potential energy possess?
k. What is the mass of an object that has 500 J of potential energy and is 120
meters off the ground?
l. How high off the ground does a 2.56 kg object have to be in order to
possess 235 J of potential energy?
m. A spring is stretched 0.2 meters from it equilibrium point how much
energy is stored in the spring? (k=25 n*m)
n. What is the spring constant (k) for a spring that has 150 J of stored energy
when it has been displaced 0.35 meters fro its equilibrium position?