Unit 4 Review

When Force applied on an object is parallel to the displacement of the object then the work done on an object is ___________________

• Parallel

• Negative

• Positive

• Zero

In which of the following situations do your arms do work on books?

• holding a heavy stack of books while standing

• carrying a heavy stack of books

• dropping a stack of books onto a table

• picking up a pile of books from the floor

Answer explanation

See figure 6-2 on p. 138

If you do 40 joules of work lifting a 10N box, how high is the shelf you move it to.

• 400m
• 40m
• 50m
• 4m

Calculate the KE of a runner that has a mass of 80 kg and is running at a velocity of 8 m/s

• 5120 J
• 320 J
• 640 J
• 2560 J

At which point is potential energy greatest?

• W
• X
• Y
• Z

As a pendulum swings from its highest to lowest position, what happens to its kinetic and potential energy? 

• Both the potential energy and kinetic energy decrease
• The potential energy decreases while the kinetic energy increases 
• The kinetic energy decreases while the potential energy increases 
• Bothe the potential energy and kinetic energy increase 

When you pull back the lever on a pinball machine and then release it to launch the ball up a ramp, which of the following energy transformations occurred? (Select all that apply)

• Kinetic --> Gravitational Potential

• Elastic Potential --> Gravitational Potential

• Kinetic --> Elastic Potential

• Chemical Potential --> Kinetic

• Elastic Potential --> Kinetic

A force of 80 N is used to pull a 10-kg block at an angle of 60 degrees (shown above) to the right. If the block moves 5 meters to the right, how much work was done on the block.

• 4000 N*m

• 200 N*m

• 2000 N*m

• 346.4 N*m

• 400 N*m

A 60.0-kg ball of clay is tossed vertically in the air with an initial speed of 4.60 m/s.  Ignoring air resistance, what is the change in its potential energy when it reaches its highest point? 

• 0 J
• 635 J
• 280 J
• 2700 J

A 0.1 kg block is released from point A, vertical distance h above the ground. It slides down an inclined track, around a circular loop of radius 0.5 m, then up another incline that forms an angle of 30 degrees with the horizontal. The block slides off the track with speed 4 m/s at point C, which is 0.5 m above the ground. Assume the entire track is frictionless and air resistance is negligible. Determine the height h.

• 2.41 m

• 1.32 m

• 0.1 m

• 1 m

Answer explanation

Initial PE must equal the KE and PE at the end of the ramp.