Download presentation

Presentation is loading. Please wait.

Published byElla Tulley Modified over 4 years ago

1
Mr. Jean November 21 st, 2013 IB Physics 11 IB Physics 11

2
The plan: Video clip of the day Potential Energy Kinetic Energy Restoring forces Hooke’s Law Elastic Potential Energy

3
Who has the most E k and by how much more?

4
How much kinetic energy does each racer have?

5
Try This: Prove that work, Potential Energy, and Kinetic energy are the same for the following: A block sitting at 0meters is slide up a frictionless inclined plane to a height of 80 meters. The block is then held in place for 50 minutes. The block is then released.

8
Elastic Potential Energy in Springs If you pull on a spring and stretch it out, you do work on the spring. W = Fd Since work is a transfer of energy, then energy must be transferred into the spring.

9
Work becomes stored in the spring as potential energy. When you stretch a spring, it has the potential to “spring” back. This is stored energy. When you compress a spring, it has the potential to “spring” forwards. This is stored energy.

10
Work & Elastic Potential Energy: E e = ½ k x 2 E e = elastic potential energy in J (joules) k = spring constant N/m (newtons per meters) x = length of extension m (meters)

11
Energy Stored in a Spring If a spring’s stretch/compression is directly proportional to the the amount of force applied to it then the elastic potential energy stored in a spring is given by: Where x is the DISTANCE the spring is stretched or compressed K is called a “spring constant”.

13
If a spring is not stretched or compressed, then there is no energy stored in it. It is in its equilibrium position. (it’s natural position)

14
Problem It requires 100 J of work to stretch a spring out 0.10 m. Find the spring constant of the spring.

16
Hookes Law: The force exerted by a spring is proportional to the distance the spring is stretched or compressed from its relaxed position. F X = -k x Where x is the displacement from the relaxed position and k is the constant of proportionality. (often called “spring constant”) x > 0

17
Conservation of Energy: m y y=0 m x x=0 E total = 1/2 mv 2 + 1/2 kx 2 = constant KE PE

18
Hooke’s Law Investigation: Start Hooke’s Law Investigation

Similar presentations

Presentation is loading. Please wait....

OK

CONSERVATION OF MECHANICAL ENERGY

CONSERVATION OF MECHANICAL ENERGY

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google