Question

Torque and Energy

You are working with your friend to build a brick fireplace. The contractor dropped 1000 - 1 kg bricks at the base of your driveway which must be carted to the build site in wheelbarrows.

Your wheelbarrow has handles that are a total of 2 m long (from the wheel to your hands), with the barrow located at 1 m (from the wheel to the center of mass of the barrow).

Your friend has a wheelbarrow where the handles are a total of 1.5 m long, with the barrow located at 0.5 m.

(A) Draw a schematic diagram of the two wheelbarrows and the forces based on the problem description.

(B) Assuming you were to load each wheelbarrow with 100 kg of bricks, which wheelbarrow will be easier to use (require less force to move)?

c) If you can lift with a maximum force of 100 N, and your friend can lift with a maximum force of 125 N, how many bricks can each of you lift in your wheelbarrow?

(D) If you and your friend make the same number of trips using your own wheelbarrows, how many trips will it take for you to move all the bricks to the build site?

(E) Ignoring wheelbarrows, and thinking of this simply in terms of energy, how much work will it take to move 1000 – 1 kg bricks from your driveway to the build site, if the distance is 50 m

(F) You are building the fireplace on a 1 m tall concrete base. Assuming the bricks all start out laying on the ground, what is the potential energy of the first layer of 15 bricks when they are placed on the 1m tall base.

Answer 1