Worksheet - Work & Power Problems

Name _____________________________________ Subject __________________, Period ____ Teacher __________________ Date ____________ Worksheet - Work & Power Problems I. Work A. Sample Problems: 1. F = 200 Newtons d = 50 meters W=? W=F*D Formula: _________________________________ W = 200 * 50 Substitution: ______________________________ Answer with unit of measure: _________________ 10,000 j 2. F = 5 Newtons W = 75 Joules D=? W/F=D Formula: _________________________________ 75 / 5 = D Substitution: ______________________________ 15 m Answer with unit of measure: _________________ 3. W = 125 Joules d = 10 meters F=? W/D=F Formula: _________________________________ 125 / 10 = F Substitution: ______________________________ 12.5 n Answer with unit of measure: _________________ 4. If 150 Joules of work is needed to move a box 10 meters, what force was used? 150 / 10 = F F = 15 n B. Fill-in-the-blank: work 1. ___________________ is done when an object moves through a distance because of a force ________________ acting upon the object. distance 2. When calculating work, you should use the formula: work = force X ____________________. Joules j 3. The SI unit for work is the _______________________. It is represented by the letter ______. C. Work Problems: 4. F = 90 N d=5m W=? ________ ________ 450 j ________ 5. F = 6 N W = 72 J d=? ________ ________ 12 m ________ 6. W = 120 J d = 24 m F=? ________ ________ 5n ________ 7. W = ? F = 62.6 N d = 13 m 813.8 j ________ ________ ________ 8. W = 13.2 J F=2N d=? ________ 9. W = 136 J ________ d = 27.2 m 6.6 m ________ F=? ________ ________ 5n ________ 10. If 360 Joules of work are needed to move a crate a distance of 4 meters, what is the weight of the crate? 360 / 4 = 90 n 11. If a group of workers can apply a force of 1000 Newtons to move a crate 20 meters, what amount of work will they have accomplished? 1000 * 20 = 20,000 j 12. If 68 Joules of work were necessary to move a 4 Newton crate, how far was the crate moved? 68 / 4 = 17 m 13. How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes. 0 joules II. Power A. Sample Problems: 1. W= 500 Joules t = 25 seconds P=? P=w/t Formula: _________________________________ P = 500 / 25 Substitution: ______________________________ 20 watts Answer with unit of measure: _________________ 2. P = 25 watts W = 5000 Joules t=? T=w/p Formula: _________________________________ T = 1000 / 25 Substitution: ______________________________ Answer with unit of measure: _________________ 200 sec 3. P = 170 watts t = 20 seconds W=? W=p*t Formula: _________________________________ W = 170 * 20 Substitution: ______________________________ 3400 j Answer with unit of measure: _________________ 4. If a man moves a large box that weighs 10 Newtons 20 meters in 30 seconds, how much power was used? 200 / 30 = 6.7 watts 20 * 10 = 200 j B. Fill-in-the-blank: Power 1. _________________________________ is the rate at which work is done. work 2. When calculating power, you should use the formula P = _________________ divided by time t for time. w stands for work, and _____ _____________. In this formula, “P” stands for power, ____ watt 3. The SI unit for Power is the ______________________. C. Power Problems 4. W = 100 J t = 10 s P=? 100 / 10 ________ ________ 10 w ________ 7. W = 500 J t = 25 s P=? ________ ________ 20 w ________ 500 / 25 5. W = 225 J P = 25 W t=? 225 / 25 _______ _______ 9s _______ 8. W = 336 J t=? P = 14 W _______ 24 s _______ _______ 336 / 14 6. P = 20 W t = 15 s W=? 20 * 15 ________ ________ 300 j ________ 9. W = ? t = 16.6 s P = 64 W 1062.4 j ________ ________ 64 * 16.6 ________ 10. A person weighing 600 N gets on an elevator. The elevator lifts the person 6 m in 10 seconds. How much power was used? 3600 / 10 = 360 watts 600 * 6 = 3600 j 11. How much time is needed to produce 720 Joules of work if 90 watts of power is used? 720 / 90 = 8 sec 12. If 68 W of power is produced in 18 seconds, how much work is done? 68 * 18 = 1224 j 13. A set of pulleys lifts an 800 N crate 4 meters in 7 seconds. What power was used? 800 * 4 = 3200 j 3200 / 7 = 457.1 watts