Mechanical Efficiency

True or False: No machine is 100 % efficient.

• True

• False

Tags

NGSS.MS-PS3-5

What is the efficiency of the machine if the input is 263 J and the output is 142 J?

• 6.26%

• 54%

• 100%

• 260%

Tags

NGSS.MS-PS3-5

Why can mechanical efficiency never be 100%?

• No machine is strong enough.

• Machines are too big to allow for 100% efficiency.

• It can be 100%.

• Some energy is lost in the form of heat/sound due to friction.

Tags

NGSS.MS-PS3-4

The _________ of a machine is always less than 100%.

• mechanical advantage

• friction

• force

• efficiency

Tags

NGSS.MS-ETS1-1

If a machine has an efficiency of 80%, and the input work is 200 J, what is the output work?

• 100 J

• 160 J

• 180 J

• 200 J

Tags

DOK Level 1: Recall

A machine does 500 J of work with an input of 1000 J. What is the efficiency of the machine?

• 25%

• 50%

• 75%

• 100%

Tags

DOK Level 1: Recall

Pulleys are never 100% efficient because of _________.

• friction

• force

• gravity

• speed

A machine has an input work of 800 J and an efficiency of 75%. What is the output work?

• 500 J

• 600 J

• 700 J

• 800 J

Tags

DOK Level 1: Recall

The percentage of the input work that is converted to output work

• mechanical advantage

• efficiency

• joule

• machine

Tags

NGSS.MS-PS3-3

NGSS.MS-PS3-4

Which of the following is NOT a factor that affects the efficiency of a machine?

• Friction

• Air resistance

• Input force

• Material of the machine

Tags

DOK Level 1: Recall