Work, Power and Energy

Scientist 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 ca you conclude about two boys having the same height and climbing the same height of stairs at different time?

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

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

• They will do the same work but use different 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 force

• I and II

• I and IV

• II and III

• III and IV

What is the unit of work?

• Newton

• Kilogram

• Joule

• Meter

Jeremy pushes a cart 3m by applying a force of 60 N. How much work does he do?

• 20 J

• 53 J

• 180 J

• 250 J

Which of the following is the form of energy associated with an object's motion?

• Potential

• Chemical

• Kinetic

• Elastic

If both the mass and the speed of a ball are doubled, the kinetic energy is increased by a factor of

• sixteen

• eight

• four

• two

An object that has potential energy has this energy because of its

• speed

• mass

• location

• acceleration

A 2-kg object and a 4-kg object are raised at the same distance above the floor. Raising the more massive object requires

• eight times as much work

• four times as much work

• twice as much work

• the same amount of work