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In the third century B.C., Archimedes said, “Give me a long enough lever and a firm fulcrum and I will lift the earth.” Disregarding the mass of the lever, and assuming the weight of the earth is 5.85 x 10^25 N, Archimedes’ weight is 858 N, and the distance from the earth to the moon is 3.84 x 10^8 m, answer the following:

a. Using the moon as a fixed fulcrum, how long a lever would Archimedes have needed to lift the earth?

A farmer uses a pulley system to raise a 225N bale of hay 16.5m. A 129N force is applied by

pulling a rope 33.0m.

a. What is the ideal mechanical advantage of the pulley system?

b. What is the actual mechanical advantage of the system?

A girl uses a lever to lift a box. The box has a resistance force of 260N while she exerts an effort

force of 175N. What is the mechanical advantage of the lever?

Sharen is competing in the local Farmer’s Fun Competition. In a wheelbarrow race, she pushes the wheelbarrow full of potting soil 25m with a force of 100N.

a) How much work has Sharen done on the wheelbarrow?

b) Sharen won the race with a time of 38s. How much power did Sharen generate over the race?

Bob is competing in the Highland Games Heavyweight events. He is tossing a 25.4kg mass for height. If he manages to toss the mass 4.5m in the air, what was the initial velocity of the mass as it leaves Bob’s hand?

Bob is competing in the Highland Games Heavyweight events. He is tossing a 25.4kg mass for height. If he manages to toss the mass 4.5m in the air, what was the initial velocity of the mass as it leaves Bob’s hand?

Brandon places a 5Ō kg crate on an inclined plane (as shown below). The coefficient of friction between

the crate and the inclined plane is 0.35. Find all forces acting on the crate and find the acceleration of the

crate. the incline is 25 degrees

Brandon places a 5Ō kg crate on an inclined plane (as shown below). The coefficient of friction between

the crate and the inclined plane is 0.35. Find all forces acting on the crate and find the acceleration of the

crate. the incline is 25 degrees

Keith is pulling a sleigh full of cranky children across a patch of ice (assume no friction). The total mass

of the sleigh + children is 5Ō kg. If Keith applies a force of 2ŌO N at an angle of 37° to the horizontal,

find the acceleration of the sleigh.

a soccer ball of mass 0.75 kg very high into the air. He observes that the soccer ball, during

its decent, stops accelerating and moves with a constant velocity What is the force of

air friction acting on the ball during terminal velocity?