Work, Energy, Power, and Conservation of Energy

A 60.0 kilogram student climbs a ladder a vertical distance of 4.00 meters in 8.00 seconds. Approximately how much total work is done against gravity by the student during the climb?

• 2.40 x 10³ J

• 3.00 x 10³ J

• 2.90 x 10² J

• 2.40 x 10² J

If 68 Joules were necessary to move a 4 Newton crate, how far was the crate moved?

• 272 m
• 17 m
• 4.05 m
• 272 cm 

A child applies a constant 20 newton force along the handle of a wagon which makes an angle of 25^o with the horizontal. How much work does the child do in moving the wagon a horizontal distance of 4.0 meters?

• 34 J

• 80 J

• 73 J

• 5.0 J

A car travels at a constant speed, v, up a hill from point A to point B. As the car travels from A to B, its gravitational potential energy __________________.

• increases and its kinetic energy remains the same

• remains the same and its kinetic energy decreases

• increases and its kinetic energy decreases

• remaines the same and its kinetic energy remains the same.

While riding a chairlift, a 55-kg skier is raised a vertical distance of 370 m. What is the total change in the skier's gravitational potential energy?

• 5.4 x 10¹ J

• 5.4 X 10² J

• 2.0 X 10⁴ J

• 2.0 X 10⁵ J

In which scenario is work = 0 J?

• Pushing a stationary wall

• Pulling a trolley car

• Pushing a book across the table

• Dropping a set of keys from a height

 The table below lists the mass and speed of four objects. Which two objects have the same KE? 
Objects    |   Mass   | Speed
A              | 1.0 kg    | 4.0 m/s 
B              | 2.0 kg    | 2 .0 m/s 
C              | 0.5 kg    | 4.0 m/s 
D              | 4.0 kg    | 1.0 m/s 

• A and C
• B and C
• A and D
• B and D 

The work done in accelerating an object along a frictionless horizontal surface is equal to the change in the object's ____________.

• potential energy

• momentum

• kinetic energy

• velocity

A horizontal force of 5.0 newtons acts on a 3.0 kg mass over a distance of 6.0 meters along a horizontal, frictionless surface. What is the change in kinetic energy of the mass during its movement over the 6.0 meter distance?

• 90 J

• 30 J

• 15 J

• 6.0 J

A 3 kg plate is tossed across the room with an acceleration of 13 m/s² in 2.5 sec. Calculate the amount of power it took to toss the plate.

• 290.5 W

• 1267.5 W

• 507 W

• 3000 W