Abook weighs 0.5 kilograms on a book shelf that is 2 meters above the ground. what is the potential energy of the book relative to the ground? (hint: you may use 10 n/kg as the value for gravity) options: a. 5 joules b. 10 joules c. 15 joules d. 20 joules

It's a snowy day and you're pulling a friend along a level road on a sled. you've both been taking physics, so she asks what you think the coefficient of friction between the sled and the snow is. you've been walking at a steady 1.5m/s, and the rope pulls up on the sled at a 32 ∘ angle. you estimate that the mass of the sled, with your friend on it, is 65 kg and that you're pulling with a force of 80 n .