Work and Kinetic Energy

You use 20 N of force to push a box 10 m. How much work do you do on the box?

• 2 J

• 2 N

• 200 J

• 200 N

A weightlifter uses 1000 N of force to lift a barbell to a height of 2 m. How much work does the weightlifter do on the barbell?

• 500 J

• 1000 J

• 2000 J

• 4000 J

You push a box with 50 N of force. It moves a distance of 10 m at a speed of 2 m/s. How much work do you do on the box?

• 100 J

• 500 J

• 20 J

• 25 J

A weightlifter lifts a 100 kg barbell to a height of 2 m. How much work does the weightlifter do on the barbell?

• 2000 J

• 200 J

• 500 J

• 50 J

You do 150 J of work lifting a 120 N backpack. How high do you lift the backpack?

• 18000 m

• 1800 m

• 1.25 m

• 12.5 m

A kid pulls a wagon at an angle of 25°, with 10 N of force. If the kid pulls the wagon for 20 m, how much work does the kid do on the wagon?

• 85 J

• 9.1 J

• 200 J

• 180 J

You push down on a shopping cart at an angle of 30°, using a force of 12 N. The cart moves at a constant speed for 15 m. How much work do you do on the cart?

• 0 J

• 160 J

• 180 J

• 90 J

You push down on a shopping cart at an angle of 30°, using a force of 12 N. The cart moves at a constant speed for 15 m. What is the force of friction on the cart, and how much work does the floor do on the cart?

• 10 N, 150 J
• 10 N, -150 J

• 12 N, 180 J

• 12 N, -180 J

You are pushing a box that weighs 10 N; the box moves 4 m, at a constant speed. How much work does gravity do on the box, and how do you know?

• 0 J, because gravity is balanced out by the normal force

• 40 J, because W = Fd = (10 N)(4 m)

• 0 J, because the force of gravity is perpendicular to the box’s displacement

• -40 J, because W = Fd = (10 N)(4 m), and gravity pulls the box down

A woman lifts a 20 kg bucket from a well at a constant speed. If she does 6000 J of work, how deep is the well?

• 30 m

• 300 m

• 600 m

• 60 m