Jacob is helping store bales of hay on his uncle's farm. The bales weigh 50 pounds and he
has to lift them up over his head to stack them. His maximum lift is 55 pounds. He finds some
rusty pulleys that he can attach about 20 feet off the ground. Which of the following is/are
important when determining if the pulleys will help him get his job done (choose all that apply).
He needs the wheels to be at least 12" across since the bales are 120" in size.
He knows it takes most of his energy to lift a bale, so he needs the pulleys to have high
efficiency so they convert almost all his energy into lifting the bale as he pulls the rope.
He has to consider the weight of the metal pulleys to calculate the efficiency
- He needs the wheels to be at least 12" across since the bales are 120" in size.
- He knows it takes most of his energy to lift a bale, so he needs the pulleys to have high efficiency so they convert almost all his energy into lifting the bale as he pulls the rope.