Using Machines

A machine is ______________________

• a device that has only one moving part

• a device that makes work easier

• a device that reduce work needed to do a job

• a device that increase work needed to do a job

Which of the following would be the correct way to report a machine's efficiency?

• 60 J

• 60 N

• 60 %

• 60 W

How can machines help you do work?

• Change the amount of force you're using

• Change the direction of your force

• Change the amount of work you're doing

• Change the distance you move something

Tags

NGSS.MS-ETS1-1

You push down on a lever with a force of 100 N to lift a 500 N box.

What is the input force?

• 500 N

• 600 N

• 400 N

• 100 N

You push down on a lever with a force of 100 N to lift a 500 N box.

What is the output force?

• 500 N

• 600 N

• 400 N

• 100 N

You did 50 J of work with a wedge that has an efficiency of 40 %. What is the output work of the wedge?

• 10 J

• 20 J

• 100 J

• 2000 J

Tags

NGSS.MS-PS3-4

The output work of the lever is 80 J

What is your input work?

• 64 J

• 80 J

• 100 J

• 640 J

Tags

NGSS.MS-PS3-5

Which is an example of how a simple machine changes the direction of a force?

• using a rope to pull a box up a hill

• using a rope and pulley to raise a flag

• using a slide to push a box down steps

• using an axle and wheel to make a wagon move forward

Tags

NGSS.MS-PS2-1

What causes the efficiency of a machine to be less than 100%?

• friction

• gravity

• input force

• reaction force

The amount by which a machine multiplies an input force is called the ____.

• efficiency factor

• fulcrum

• mechanical advantage

• resistance force