Mechanical Advantage, and Efficiency

Hey! This worksheet is about Power,

1) A force of 40N is exerted on a mass causing it to move with a constant speed of 5 m/s. What power is used?

2) A girl weighing 500N takes 50 seconds to climb a flight of stairs 18 meters high. What is her vertical power output?

3) 95 kg Spiderman climbs a 4.0 m spider web in 3.0 seconds. What is the power output of Spiderman?

4) A force of 575N is applied to a lever, and therefore pushed down 1.3 meters. The other end raises a 100 kg car two thirds of a meter.

a) What is the work going into the system?

b) What is the weight force pulling the system down?

c) What is the work done by the weight force?

d) What is the total work lost by the system?

e) What is the Mechanical advantage of the lever?

5) You and your friend Steve take your truck mudding and get it stuck in the mud. Ya’ll use a tree branch as a lever to lift the truck out of the mud. You apply an effort force of 700N to the branch and the back of the truck weighs 2100N. What is the mechanical advantage of the tree branch lever?

6) Marc is asked to raise a flag at the Remembrance Day ceremonies at his school. If the effort force to raise the flag is 50N and the load force—the flag plus the rope—is 50N what is the mechanical advantage of the pulley on the flagpole?

7) Justin is riding his bike up Dunmore Hill. The effort force from his feet on his pedals is 1160N. The resulting load force to move the bike forward is 675N. What is the mechanical advantage of the bike?

8) A machine is 75% efficient, and the work put into it is 4800 Joules. What is the work output?

9) A machine moves a 600 N object 6 meters. If the amount of work put into the machine is 4500 Joules, what is the efficiency of the machine?

10) A boy exerts a force of 225 N on a lever to raise a 103 N rock a distance of 13 cm. If the efficiency of the lever is 88.7%, how far did the boy move his end of the lever?