Presentation on theme: "For Your Consideration…"— Presentation transcript:
1For Your Consideration… You lift a 2 kg textbook from the floor to a shelf 2.10 m above the floor.(a) What is the book’s gravitational potential energy relative to the floor?(b) What is the gravitational potential energy relative to your head, assuming you’re 1.65 m tall?
2For Your Consideration… In an isolated system, which of the following is a correct statement of the quantity that is conserved? (a) kinetic energy (b) potential energy (c) kinetic energy plus potential energy (d) both kinetic energy and potential energy
3For Your Consideration… A piece of ice with mass 15 kg falls from a roof 8.00 m above the ground. What is the speed of the ice when it reaches the ground?
4For You to Consider…A bowling ball is suspended from the ceiling of a lecture hall by a strong cord. The ball is drawn away from its equilibrium position and released from rest at the tip of the demonstrator’s nose. If the demonstrator remains stationary, explain where the ball upon its return
5For You to Consider…Would this demonstrator be safe if the ball were given a push from its starting position at her nose?
6Please Work Out the Following… A block of mass m is projected across a horizontal surface with an initial speed v. It slides until it stops due to the friction force between the block and the surface. The same block is now projected across the horizontal surface with an initial speed 2v. When the block has come to rest, how does the distance from the projection point compare to that in the first case?
7Please Check This Out…A baseball is thrown straight up with initial speed vi. If air resistance cannot be ignored, when the ball returns to its initial height its speed is less than vi. Explain why, using energy concepts