Ch. 14.3 - Mechanical Advantage and Efficiency

Ch. 14.3

Mechanical Advantage and Efficiency

Multiple Choice

Why is the actual mechanical advantage of a machine always less than its ideal mechanical advantage?

• The actual mechanical advantage takes into account friction

• The actual mechanical advantage doesn't take into account friction

• The actual mechanical advantage doesn't involve force

• The actual mechanical advantage is stronger than ideal mechanical advantage

Fill in the Blanks

You test a machine and find that it exerts a force of 5 N for each 1 N of force you exert operating the machine. What is the actual mechanical advantage of the machine?

AMA = Output force / Input Force

**There are no units for actual mechanical advantage, just type a number**

Multiple Choice

Why can no machine be 100% efficient?

• Because machines always have flaws

• Because friction is always present

• Because of human error

• Because batteries run out of power

Multiple Choice

Which of the following is the correct equation to calculate efficiency?

• (Work Output/Work Input)

• (Input Distance/Output Distance) x 100%

• (Work Output/Work Input) x 100%

• (Input Force x Input Distance) x 100%

Open Ended

Suppose you are an inventor in 1900. You are constructing a bicycle of your own design. What could you do to ensure your bicycle efficiently changes the work input into forward motion?

Fill in the Blanks

You have just designed a machine that uses 1000 J of work from a motor for every 800 J of useful work the machine supplies. What is the efficiency of your machine?

Efficiency = (Work Output / Work Input) x 100%

**Give Your Answer As A Percentage**

Fill in the Blanks

If a machine has an efficiency of 40%, and you do 1000 J of work on the machine, what will be the work output of the machine?

Efficiency = (Work Output / Work Input) x 100%

**Include the units of Joules (J) in your answer**