Act 7. Quiz. Work, Power, MA, Efficiency. Op 1

What is transferred when work is done?

• Velocity

• Energy

• Matter

• Mass

Which must be true if a machine’s mechanical advantage is equal to 2?

• Direction of force is changed

• Output force equals input force

• Output force is greater than the input force

• Output work is greater than the input work

Using an inclined plane to lift a heavy object allows you to apply:

• No force

• A lesser force

• The same force

• A greater force

If someone is climbing stairs at a certain rate, then it climbs them faster, which one is increasing?

• Work

• Efficiency

• Power

• Force

What is the input force?

• The force that the machine applies.

• The force the human applies.

• The sum of the human’s force and the machine’s force.

• The substraction of the human’s force and the machine’s force.

A girls uses 10 N of force to carry a bag of apples 3 m from the kitchen counter to the table. How much work does she do?

• 3 J

• 30 J

• 3 W

• 30 W

A boy does 400 J of work moving a wheelbarrow for 20 seconds. How much power does he use?

• 20 W

• 20 J

• 80 W

• 80 J

A construction worker runs 300 m in 15 s while holding a sack of sand. Having a Power of 533 W, A) How much work did they do? B) What force did they use?

• A) W = 7995 J / B) F = 26.65 N

• A) W = 7995 J / B) F = 31.98 N

• A) W = 7845 J / B) F = 31.98 N

• A) W = 7845 J / B) F = 26.65 N

How much work does a leopard on an impala of 60 kg if it lifts it into a tree, at 4.3 m from the ground?

• W = 2530.1 J

• W = 258 J

• W = 13.95 J

• W = 588.6 J

How many seconds are needed to do a work of 500 J with a power of 100 W?

• 5 s

• 50000 s

• 400 s

• 600 s