Work, power and simple machines

Question 1 of 10

Work is done when you push a wall that does not move.

Question 2 of 10

A machine lifts a load of 400 N through 1 m when an effort of 100 N moves through 10 m. Calculate (a) the mechanical advantage, (b) the velocity ratio, (c) the efficiency.

Question 3 of 10

Simple machines create energy.

Question 4 of 10

A machine lifts a load of 800 N through 1 m when an effort of 200 N moves through 5 m. Calculate (a) the mechanical advantage, (b) the velocity ratio, (c) the efficiency.

Question 5 of 10

A pulley can change the direction of a force.

Question 6 of 10

A machine does 4,800 J of work in 20 s. Find its power.

Question 7 of 10

A force of 20 N pushes a box 12 m. Find the work done.

Question 8 of 10

A boy of mass 50 kg climbs stairs 2 m high. Taking g = 10 N/kg, the work he does is ___ J.

Question 9 of 10

Tweezers (forceps) are levers of the

Question 10 of 10

The watt is the unit of power.