Chapter 3 Lesson 2 Review (Using Machines)

Any device that can make work easier is known as a

• kinetic energy

• machine

• potential energy

• pendulum

Can a machine decrease the amount of work done?

• Yes

• No

• Sometimes

This is the force applied to any machine, or the EFFORT FORCE. It is the work done by you on a machine.

• input force

• power

• output force

• mechanical advantage

This is the force exerted by a machine, or the RESISTANCE FORCE. This is the work done by the machine.

• input force

• power

• output force

• mechanical advantage

This is the force that CAUSES movement.

• Input work

• Output work

This is the force that MAKES an object move.

• Input work

• Output work

TRUE or FALSE: Machines change input force to output force.

• True

• False

How does a crowbar make work easier?

• By increasing the distance of the force.

• By increasing the size of the output force.

• By decreasing the size of the output force.

Answer explanation

A crowbar makes work easier by increasing the size of the output force, allowing for more force to be applied with less effort.

Machines make work easier by all of the following ways except

• changing the amount of force

• changing the direction of force

• changing the amount of friction applied to the force

• changing the distance of force

How can a machine make work easier WITHOUT CHANGING the amount of the force or the distance over which the force acts?

• By decreasing friction.

• By reducing the amount of work needed.

• By changing the direction of the force.