Review: Momentum, Impulse, Work, Energy, Power

A box moves 10 m horizontally when force F = 20 N is applied at an angle

 $\theta\ \ =\ 30\degree$  
What is the work done on the box by F during the displacement?

• −200 J

• 173 J

• - 173 J

• 200 J

Answer explanation

We know this work is positive because the direction of motion is in the same direction as the force (angle less than 90)

Tags

NGSS.HS-PS3-1

______________ is a force acting over some amount of time to cause a change in momentum

• Work

• Impulse

• Energy

• Power

Tags

NGSS.HS-PS2-3

_______ is a force acting over some amount of distance to cause a change in energy

• Impulse

• Momentum

• Work

• Energy

True or False: Negative work means that work was done in the negative direction.

• True

• False

Answer explanation

Negative work means the force is opposing the direction of motion.

Work is a __________.

• Scalar

• Vector

A force that does positive work is ...

• giving energy to the object

• taking energy from the object

• neither giving nor taking energy from the object

Answer explanation

When you do work to lift a weight over your head, you are giving the weight potential energy.

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

Work is measured in ________.

• Joules

• Watts

• Newtons

• kg m/s

Answer explanation

Also sometimes called a newton-meter

Tags

NGSS.HS-PS2-1

A box moves 5 m horizontally when a force, F = 10 N is applied at an angle (120 degrees) as shown. What is the work done on the box by F during the displacement

• -44 J

• 25 J

• -25 J

• 44 J

Answer explanation

We know the work is negative because the force is against the direction of motion.

Tags

NGSS.HS-PS3-2

Only forces that act __________ to the displacement of an object do work on that object.

• parallel

• perpendicular

Answer explanation

perpendicular forces (to the motion of the object) do no work on that object.

A box moves 10 m horizontally as a force F = 20 N is applied downward. What is the work done on the box by F during the displacement?

• 0 J

• 200 J

• -200 J

• 20 J

Answer explanation

perpendicular forces do no work on the object.

Tags

NGSS.MS-PS3-5