Work, Energy, and Power

At a park, Emma, Noah, and Liam are playing. There is a slide that is 6.0 meters in length and inclined at an angle of 45ᵒ. Noah places a toy truck that weighs 30 newtons at the top of the slide (height 4.0 meters above the ground) and allows it to slide down. The work done on the toy truck by gravitational force during the six-meter slide down the slide is most nearly

• 30 J

• 90 J

• 120 J

• 150 J

During a physics class, Emma and Noah are discussing the concept of work. Emma argues that pulling a 15 kg sled (assuming no friction) up a 30 m hill to a height of 10 m requires more work. On the other hand, Noah believes that lifting the same sled vertically to a height of 10 m requires more work. Their physics teacher, Mr. Smith, asks you to determine who is correct. Who is right?

• Emma, who thinks pulling the 15 kg sled up a 30 m hill to a height of 10 m requires more work.

• Noah, who thinks lifting the same sled vertically to a height of 10 m requires more work.

• Both Emma and Noah are correct, as both actions require the same amount of work.

• Neither Emma nor Noah is correct, as neither action requires any work.

Oliver, Sophia, and Mia are working on a physics project. They want to determine which of the following needs more force: pushing a 15 kg block of ice (using ice to minimize friction) up a 30 m ramp to a height of 10 m or lifting the same block straight up to a height of 10 m. What do you think?

• Pushing the 15 kg block of ice up a 30 m ramp to a height of 10 m.

• Lifting the same block vertically to a height of 10 m.

• Both pushing the ice up the ramp and lifting it require the same amount of force.

• Neither pushing the ice up the ramp nor lifting it requires any force.

Elijah is pushing a block of mass m a distance x across a surface with negligible friction. He applies a force F at an angle f above the horizontal, as shown in the figure. The work done by Elijah over this interval is:

• Fmgx

• Fmgxcos∅

• Fxcos∅

• Fxsin∅

Which scenario requires more work?

• Option 1--Abigail lifting her physics book one meter off her desk in one second.

• Option 2--Henry lifting his physics book one meter off his desk in two seconds.

• Both scenarios (Abigail & Henry) require the same amount of work.

• Neither scenarios (Abigail nor Henry) require any work.

Ethan is lifting weights at the gym. He notices that the rate at which he is doing work is called what?

• potential energy

• kinetic energy

• work

• power

Ava, a weight lifter, lifts a mass m at a constant speed to a height h in time t during her workout. What is the average power output of Ava during this exercise?

• mg

• mh

• mgh

• mgh/t

Rohan, Aiden, and Lily are playing with a ball on a hill. The energy stored in the ball due to its position on the hill is called

• potential energy

• kinetic energy

• work

• power

Anika, Mia, and Charlotte are observing a moving car. They notice that the car has energy due to its state of motion. This type of energy is called:

• potential energy

• kinetic energy

• work

• power

In their physics class, Mia and Noah are performing an experiment. They push a 3.0 kg block of ice with a speed of 6.0 m/s across a wet lab table. What is the kinetic energy of the block of ice?

• 0 joules

• 18 joules

• 36 joules

• 54 joules