A Yes B No C Need more information

A: Yes B: No C: Need more information A hockey puck slides without friction along a frozen lake toward an ice ramp and plateau as shown. The speed of the puck is 4 m/s and the height of the plateau is 1 m. Will the puck make it all the way up the ramp? v = 4 m/s h = 1 m

Gravitational Potential Energy PEg Spring Potential Energy PEs Kinetic Energy KE Energy

Spring displacement F 2 F 0 Δx 2Δx x force

Hooke’s law displacement –F -Δx 0 Δx 2Δx Fext = k Δx Δx Spring Constant -F Fspring = - k Δx Restoring Force F 2 F -Δx force Δx is proportional to F

Spring displacement 1/k k 2 2 0 x k 1 1/k 1 Hooke’s law force F = k Δx k 1 > k 2

How to measure? Typical values Units

Spring Energy force F 2 F 0 Δx 2Δx Work Done by a Varying Force x F F = k Δx PEsf – PEsi = Work δx Area = F×δx displacement Area = Work! W = ½ kx 2

1. Define a system 2. Define the initial and final states 3. Draw an Energy Bar Chart (Work? !) 4. Write the Energy-Work Formula No Friction ΔE = W After Before Δx KEi PEgi PEsi W V-? KEf PEgf PEsf + k m 0 - ½ kx 2 = ½ mv 2

1. Define a system 2. Define the initial and final states 3. Draw an Energy Bar Chart (Work? !) 4. Write the Energy-Work Formula No Friction ΔE = W After Before KEi PEgi PEsi W V-? Hmax ? KEf PEgf PEsf + 0 k - ½ kx 2 = ½ mv 2+mgh

1. Define a system 2. Define the initial and final states 3. Draw an Energy Bar Chart (Work? !) 4. Write the Energy-Work Formula ΔE = W Friction: μs and μk Before KEi PEgi PEsi W Δx k Hmax ? θ + 0 - After KEf PEgf PEsf

Homework Due Monday Chapters 5. 4, 5. 5 + Read 5. 6 Power!!! # 20, 35, 39, 53, 59

Quiz A ball is dropped from a tower and attains a speed v at the bottom. To achieve a speed 2 v at the bottom, how many times as high must the new tower be?