A 30 kg boy stands on rough horizontal ground. The coefficient of static friction,
us is 0.8. The present static friction between the boy and the ground is
?

While goofing off at the ice skating rink, a student takes off her shoes and places each of them on the ice. her friend, a hockey player, then shoots a hockey puck at each shoe. the first puck immediately comes to rest after it collides with the left shoe. the second puck rebounds after it collides with the right shoe. if each hockey puck has the same incoming speed, which shoe has greater speed after the collision? the right shoe. both shoes have the same speed. the left shoe.

This energy transformation diagram represents the energy of a skateboarder moving along a half-pipe. as she skates toward the top of the half-pipe, her original kinetic energy is converted to potential energy and friction. how much of the energy is potential?

The california mussel (mytilus californianus) attaches itself to a rock or other solid surface with a bundle of filaments known as the byssus. imagine that 15.0 j of work is done to stretch the distal end of the byssus. it releases 10.8 j of thermal energy as it relaxes. what is the resilience of the distal end of the byssus?