Your car runs out of gas and you get out and push it. If you apply a force of 1030 N for 327 m (the distance to the nearest gas station), how much work did you do to push it?
Question 23
23.
What amount of work can a 600.-W do in 3.00 minutes?
Question 24
24.
A 25.0-kg girl climbs up a tree branch 3.0 m higher in 6.00 seconds. What is her power output?
Question 25
25.
The 2.0-kg head of an ax is moving at 3.0 m/s when it strikes a log and penetrates 0.030 m into the log. What is the average force the blade exerts on the log?
Question 26
26.
Casey and Ryan, pretending that they are playing in the jungle, suspend a rope from an overhead tree limb. Casey, of mass, 39.6 kg, runs horizontally at 8.09 m/s along the flat ground, grabs the rope, and swings off the level ground.
(a) How high does Casey get above the ground in his swing?
Question 27
27.
Casey and Ryan, pretending that they are playing in the jungle, suspend a rope from an overhead tree limb. Casey, of mass, 39.6 kg, runs horizontally at 8.09 m/s along the flat ground, grabs the rope, and swings off the level ground.
(b) Ryan, who is 26.6 kg, gives it a try and reaches a height of 3.13 meters above the ground? How fast was Ryan running to achieve this height?
Question 28
28.
EXTRA CREDIT: The coyote, whose mass is 24.62 kg, is chasing the roadrunner when the coyote accidentally runs off the edge of a cliff and plummets to the ground 89.7 m below. What force does the ground exert on the coyote as he makes a coyote-shaped dent 0.695 m deep in the ground?
Question 29
29.
A 37.06 kg hammer of a pile driver is lifted 16.8 m .
a) Find the potential energy of the driver at its maximum height.
Question 30
30.
A 37.06 kg hammer of a pile driver is lifted 16.8 m .
b) Calculate the velocity of the driver as it hits the ground when dropped from 16.8 m using the Work-Energy Theorem.
Question 31
31.
EXTRA CREDIT: A child is on a swing. Her mom pushes her to a height of 2.21 m above the starting position. Determine the child's maximum velocity during the swing.
In physics, work is defined as
force times time.
force divided by distance.
distance divided by time.
force divided by time.
force times distance.
If you lift two loads up one story, how much work do you do compared to lifting just one load up one story?
One quarter as much
One half as much
The same amount
Twice as much
Four times as much
If Nellie Newton pushes an object with twice the force for twice the distance, she does
twice the work.
the same work.
four times the work.
eight times the work.
The unit of work is the
watt.
meter.
joule.
newton.
second.
Power is defined as the
force on an object times the distance the object moves.
work done on an object divided by the time taken to do the work.
work done times the time taken to do that work.
distance divided by the time taken to move that distance.
force on an object divided by the time the force acts.
The unit of power is the
joule
newton
second
watt
meter
Potential energy is the energy an object has because of its
speed
density
location
size
temperature
Kinetic energy of an object is equal to
its mass multiplied by its acceleration.
one half the product of its mass times its speed.
one half the product of its mass times its speed squared.
its mass multiplied by its acceleration squared.
its mass multiplied by its speed.
An arrow in a bow has 80 J of potential energy. Assuming no loss of energy to heat, how much kinetic energy will it have after it has been shot?
160 J
80 J
60 J
40 J
0 J
Energy is changed from one form to another with no net loss or gain.
Always false
Always true
Sometimes true
As a pendulum swings back and forth
all of these choices
potential energy is transformed into kinetic energy.
at the lowest part of its swing, its energy is all kinetic.
kinetic energy is transformed into potential energy.
at the end points of its swing, its energy is all potential.
When a car’s speed triples, its kinetic energy
none of these choices
remains the same.
triples
increases by nine times.
increases by four times.
Rockets are launched from an airplane in the forward direction of motion. The kinetic energy of the airplane will be
increased.
unchanged.
decreased.
A woman can lift barrels a vertical distance of 1meter or can roll them up a 2-meter long ramp to the same elevation. If she uses the ramp, the applied force required is
4 times as much
1/4 as much
the same amount
1/2 as much
2 times as much
A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of
power
energy
both energy and power
none of these choices
An object that has kinetic energy must be
moving
elevated
falling
at rest
Which requires more work: lifting a 40-kg sack vertically 5 meters or lifting a 20-kg sack vertically 10 meters?
Both require the same amount of work.
Lifting the 20 kg sack
Lifting the 40 kg sack
Which has greater kinetic energy, a car traveling at 35 km/h or a half-as-massive car traveling at 70 km/h?
The 70 km/h car
The 30 km/h car
Both have the same kinetic energy.
An object at rest may have
energy
speed
velocity
momentum
none of the above
A heavy object and a light object are released from rest at the same height and time in a vacuum. As they fall, they have equal