# Glencoe Science Level Blue

## Chapter 20: Work and Simple Machines

### Calculating Efficiency

 1 You do 222 J of work pushing a box up a ramp. If the ramp does 200 J of work, what is the efficiency of the ramp? A) 96% B) 82% C) 75% D) 90% 2 You do 15,000 J of work with a screw jack. If the screw jack does 14,500 J of work, what is the efficiency of the screw jack? A) 75% B) 88% C) 97% D) 55% 3 You do 1200 J of work with gears. If the gears do 1000 J of work, what is the efficiency of the gears? A) 75% B) 83% C) 77% D) 89% 4 You do 50 J of work with a lever. If the lever does 45 J of work, what is the efficiency of the lever? A) 90% B) 85% C) 95% D) 97% 5 You do 1260 J of work with a wheel and axle. If the wheel and axle does 1200 J of work, what is the efficiency of the wheel and axel? A) 97% B) 88% C) 84% D) 95% 6 You do 75 J of work with a wedge. If the wedge does 65 J of work, what is the efficiency of the wedge? A) 92% B) 90% C) 87% D) 95% 7 You do 42 J of work with scissors. If the scissors do 40 J of work, what is the efficiency of the scissors? A) 75% B) 95% C) 78% D) 80% 8 You do 400 J of work with a pulley. If the pulley does 380 J of work, what is the efficiency of the pulley? A) 95% B) 90% C) 77% D) 98% 9 You do 260 J of work pushing a box up a ramp. If the ramp does 200 J of work, what is the efficiency of the ramp? A) 85% B) 73% C) 83% D) 77% 10 You do 280 J of work with a pulley. If the pulley does 275 J of work, what is the efficiency of the pulley? A) 92% B) 95% C) 98% D) 70%