1. Ch. 4 slides
Forces.ppt

2. Elevator
A 1000-kg elevator hangs from a cable. Find the tension in the rope for each of the following situations (include a motion diagram, identify the forces, and draw a free body diagram on your way to the solution):
The elevator is stationary.
The elevator is moving upward at a steady speed of 5 m/s.
The elevator is accelerating upward at 5 m/s2.
The elevator is accelerating downward at 5 m/s2
Forces.ppt

3. Extended free body diagrams
For the following situations draw separate free body diagrams (FBD’s) for each object listed. Label the forces in the form FBonC, NSonC, etc…. Link any 3rd law pairs with a dotted line.
A dog and a kid involved in tug-of-war with a rope. The dog is winning (draw FBD’s for the dog and for the kid)
A woman riding in an elevator that’s accelerating upwards (draw FBD for woman and elevator)
A mass hanging off the end of a table is attached by a string over a pulley to a frictionless cart (draw FBD’s for the cart and the mass.
Forces3rd1.ppt

4. Two blocks being pushed
Box 1 (m1 = 3 kg) and box 2 (m2 = 1 kg) contain poisonous gas. You need to push them together (you have no time to push each separately) off a cliff. You push with your maximum force of 4 N.
If the interior forces (i.e. the force of one box on the other) are too large, the boxes will break, releasing the poisonous gas. Which box should you put in front? Does it matter? For simplicity assume the cliff is frictionless.
a) Find the acceleration of the blocks.
b) Find the force between the two blocks.
c) Put the applied force on the other box. Repeat a) and b).
Forces3rd3.ppt

5. Component equations
Write down the Newton’s 2nd law component equations for the following free body diagram
Forces.ppt