Do Now 1 Calculate the distance between two
Do Now: 1. Calculate the distance between two 75 kg individuals that have a gravitational attraction of 8. 34 x 10 -7 N.
Aim: How do we relate work and energy? Do Now: Quiz HW: Problem Set
Demos 1. Pulling Jeff around the room. 2. Jeff lifting up his desk 3. Jeff holding his desk 4. Jeff’s desk sitting there without Jeff
Work: Energy transferred by a force. Energy: Ability to do work • W = FIId Cosθ Unit: Joule (J) • Energy or Work is a scalar quantity Dakota pulls Alicia 20 meters with a rope at a 30 o angle and in doing so applies a force of 10 Newtons. How much work does he do?
More on Work… A person is trying to push a heavy box across a classroom floor, but the box does not move. Is work being done on the box? • NO! In order for work to be done on the box it must MOVE!
Doing work on an incline 30 m 35 N • A box is pulled up a 30 meter long inclined plane at an angle of 30º with a force of 35 Newtons at constant speed. Calculate the work done by the 35 N force in moving the box. WORK IS DONE IN THE DIRECTION OF THE NET FORCE!!! If distance and Force are Parallel then we are O. K!!!
Station 1 15 N 40° • A wagon is pulled a horizontal distance of 5 meters with a force of 15 Newtons at an angle of 40º above the horizontal. How much work is done?
Station 2 A 50 kg crate full of twinkies is pushed 30 meters up a 20 o incline with a constant speed and force of 200 N. What is the work due to friction? (Hint: Sketch)
Summary What is the definition for work? What is the exact equation for work? What are the units? The Whole World is Made of Energy
- Slides: 9