Work, Power, and Energy

Which of the following best describes work?

• product of force and displacement

• energy consumed per unit time

• push or pull on an object

• ability to create change

Which of the following is a unit of work?

• Coulomb

• Joule

• Newton

• Ohm

Which of the following best describes power?

• force exerted per unit of time

• change of acceleration per unit of time

• change of momentum per unit of time

• work done per unit of time

Scientists say that "work" is done in the following cases EXCEPT

• pushing a door

• pulling a schoolbag

• lifting a pail of water

• carrying a chair across the room

In a marathon, the winner and the runner-up have the same mass. Compared with the runner-up, the winner has more _____________.

• energy

• force

• power

• work

What can you conclude about two boys having the same weight and climbing the same height of stairs at different times?

• They will do different work but use the same power.

• They will do the same work and use different power.

• They will do the same work and use the same power.

• They will do the same work and have no power.

Which of the following factors would affect the amount of work done?

I. amount of force

II. shape of the object

III. speed of the object

IV. displacement in the direction of the net force

• I and II

• I and IV

• II and III

• III and IV

Is there a work done when the force applied is perpendicular to the displacement of the object?

• There is work done.

• There is no work done.

Is there a work done when the force applied is directed opposite to the displacement of the object?

• There is work done.

• There is no work done.

Is there a work done by placing a book on your head and walking for a displacement of 3m to the right?

• None, because 3m is not enough for a displacement.

• Yes, because you've exert enough force to move the object to a distance.

• None, because the force applied is perpendicular to the displacement of the book.

• Yes, because there is a force applied perpendicular to the displacement of the book.