1. Sketch a position vs. time graph for a system moving under a constant net force.
A mosquito collides head on with a car traveling 60 mph.  How do you think the size of the force the car exerts on the mosquito compares to the size of the force that the mosquito exerts on the car.  Show free body diagrams for the car and the mosquito at the moment of collision showing only the horizontal forces..  
Quiz

2. Tension of the rope
T=?
100N
a=?

3. Equilibrium (the first lab!)
Find the rope tension
60°
30°
10kg x y
Draw a free body diagram
Set Cartesian coordinates (make a smart choice)
Find all x and y components of all forces
Write down Newton’s Second Law for the components

4. Equilibrium (the first lab!)
Find the ropes’ tension
60°
30°
10kg x y T2 W T2 T1 y x T1 T1 T2
-mgcos60°
-mgcos30° W

5. A child of mass m rides on a sled down a slick, ice-covered hill inclined at an angle θ with respect to the horizontal.
Draw a sketch
Draw a free body diagram
Set Cartesian coordinates (make a smart choice)
Find all x and y components of all forces and the acceleration
Write down Newton’s Second Law for the components
Quiz
Hint: Remember, that normal force is always perpendicular to a surface

6. Homework
(due Friday)
Section 4.5 Problems (p.112)
#19, 23, 24, 25, 27