Q4 Physics Master

No work is done when:

• A book is dropped on the ground.
• A book is lifted straight up off the ground.
• A book is pushed across a table.
• A book is at rest on a table.

Work done on a body depends on the magnitude of the force, displacement made and the cosine of the angle between the force and the displacement.

• True
• False

In physics, the use of force to move an object is called _____.

• Work
• Watts
• Mass
• Momentum

What is the unit of work in SI system?

• Joule
• Erg
• Kilogram meter
• None of these

The amount of work done depends on the

• amount of force applied.
• mass and distance the object moves.
• mass and speed with which the object moves.
• amount of force and distance the object moves

If the change in kinetic energy of a hockey puck hit across the ice by a hockey stick is 200 joules, and the average force that the stick exerts on the puck is 200 N, what is the distance that the force is exerted over?

• 1.2 m
• 1 m
• 0.8 m
• 0.4 m
• 0.6 m

How much work is done by the force of gravity when a 45 N object falls to the ground from a height of 4.6 m?

• 207 Joules

• 217 Joules

• 198 Joules

• 192 Joules

A workman carries some lumber up a staircase. The workman moves 9.6 m vertically and 22 m horizontally. If the lumber weighs 45 N, how much work was done by the workman?

• 432 Joules
• 990 Joules
• 1,422 Joules
• 865 Joules

A machine increases the amount of work that is done

• True
• False

A resistance force is 225 N and the mechanical advantage is 1.74. What is the effort force?

• 129 N
• 135 N
• 391 N
• 227 N