Simple Machines

A construction worker uses a board and log as a lever to lift a heavy rock. If the input arm is 2 meters long and the output arm is 0.5 meters long, what is the mechanical advantage of the lever?

• 4

• 8

• 0.25

• 1

A rake is held so that its effort (input) arm is 0.5 meters and its resistance (output) arm is 1.5 meters. What is the mechanical advantage of the rake?

• 3

• .3333

• 1

• 0

Jack & Jill went up the hill to fetch a pail of water. At the well, Jill turned the crank handle of radius 0.500 m to rotate the axle of radius 0.100 m. What is the ideal mechanical advantage of the wheel?

• 1

• 0

• 5

• 0.20

A block and tackle system is used to lift a small child from the bottom of a well. It lifts with 80 N of force. The input force required to lift this weight using the block and tackle is 40 N. What is the mechanical advantage of the block and tackle?

• 2

• 1

• 0.5

• 0

A bicycle wheel has a MA of 0.25. If an input force of 100 N was provided by gear system, what would the output force on the wheel have been?

• 2.5 N

• 1

• 0 N

• 25 N