Force, Work, Power and Pressure

1) A person lifts a package weighing 75 N. If she lifts it 1.2 m off the floor, what work has she done?

• 90 J

• 62.5 J

• 6.25 J

• 900 J

Tags

NGSS.MS-PS3-4

2) When 142 J of work is done in pushing a box horizontally 13.3 m, how much force is applied?

• 10.7 W

• 18,886 N

• 10.7 N

• 1,888.6 N

3) What work is done when a person pushes a refrigerator weighing 720 N across a floor 12 m? (The force of friction between the refrigerator and the floor is 480 N.)

• 20 J

• 5,760 J

• 8,640 J

• 2,880 J

4) A 5 kg block is pulled across a table by a horizontal force of 40 N with a frictional force of 8 N opposing the motion. Calculate the acceleration of the object.

• 0.15625 m/s2

• 6.4 m/s2

• 200 m/s2

• 320 m/s2

Tags

NGSS.MS-PS2-2

5) If a 60 kg person on a 15 kg sled is pushed with a force of 300 N, what will be the total acceleration?

• 5 m/s2

• 22,500 m/s2

• 4 m/s2

• 0.4 m/s2

Tags

NGSS.MS-PS2-2

6) An object of mass 30 kg is in free fall in a vacuum where there is no air resistance. What is the force on the object if acceleration of gravity on Earth is (g = 9.81 m/s²)?

• 3.06 N

• 294.3 N

• 294.3 N

• 0.327 N

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

7) An object of mass 30 kg is in free fall in a vacuum where there is no air resistance. What is the force on the object on Mars?

Hint: Google “acceleration of gravity mars”

• 111.33 N

• 8.08 N

• 0.1237 N

• 8.08 J

Tags

NGSS.MS-PS2-2

8) How much pressure is the house exerting on the ground?

• 1,400 P

• 175 P

• 350 P

• 2,800 P

9) A horse performs 15,000 Joules of work pulling a wagon for 20 seconds. What is the horse’s power?

• 300,000 J

• 750 W

• 300,000 W

• 0.001 W

What is the acceleration of this object?

• 80 m/s2

• 2.5 m/s2

• 5 m/s2

• 7.5 m/s2

Tags

NGSS.MS-PS2-2