Chapter 10.2: Simple Machines

Which are true about machines?

• 1. They are all simple.

• 1. They may be powered by engines or people.

• 1. They make tasks easier.

• 1. They ease the load by changing the force.

The work that a person does on a machine is called

• Output work

• Resistance force

• Input work

• Effort force

The work that the machine does is called

• Output work

• Resistance force

• Input work

• Effort force

The force exerted by a person on a machine is called

• Mechanical advantage

• Resistance force

• Input work

• Effort force

The force exerted by the machine is called

• Mechanical advantage

• Resistance force

• Input work

• Effort force

Which is correct about mechanical advantage?

• 1. It is equal to the displacement of the effort force, divided by the displacement of the load

• 1. It is equal to the displacement of the load, divided by the displacement of the effort force

• 1. It is the ratio of resistance force to effort force.

• 1. It is the ratio of effort force to resistance force.

Which is correct about ideal mechanical advantage?

• 1. It is equal to the displacement of the effort force, divided by the displacement of the load

• 1. It is equal to the displacement of the load, divided by the displacement of the effort force

• 1. It is the ratio of resistance force to effort force.

• 1. It is the ratio of effort force to resistance force.

Which are true about efficiency?

• 1. It is the ratio of input work to output work.

• 1. It is the ratio of output work to input work.

• 1. It is equal to its mechanical advantage, divided by the ideal mechanical advantage, multiplied by 100.

• 1. It is equal to its ideal mechanical advantage, divided by the mechanical advantage, multiplied by 100.

A sledgehammer is used to drive a wedge into a log to split it. When the wedge is driven 0.20 m into the log, the log is separated a distance of  5.0 cm. A force of 1.7 x 10^4 N is needed to split the log, and the sledgehammer exerts a force of 1.1 x 10^4 N. What is the mechanical advantage of the wedge?

• 0.25

• 4.0

• 0.65

• 1.5

A sledgehammer is used to drive a wedge into a log to split it. When the wedge is driven 0.20 m into the log, the log is separated a distance of  5.0 cm. A force of 1.7 x 10^4 N is needed to split the log, and the sledgehammer exerts a force of 1.1 x 10^4 N. What is the ideal mechanical advantage of the wedge?

• 0.25

• 4.0

• 0.65

• 1.5