1. Physics Team Think-a-thon Period: Team members:
Laws of Motion and Friction October 4 - 6, 2016
1) If we assume there is no air resistance, what will be the acceleration of a rock thrown straight upward at the moment it reaches the very top of its trajectory and why?
2) If we assume there is air resistance, what will be the acceleration of a rock thrown straight upward at the moment it reaches the very top of its trajectory and why?

2. Physics Team Think-a-thon
Laws of Motion and Friction October 4 - 6, 2016
3) A 1-kg rock is thrown at 10 m/s straight upward. If we assume there is no air resistance, what will be the net force that acts on the rock when it is half way to the top of its path and why?
4) Consider the apple at rest on the table. If we call the gravitational force exerted on the apple the “action” force, then what is the “reaction” force according to Newton's 3rd law? Draw it on the diagram.

3. Physics Team Think-a-thon
Laws of Motion and Friction October 4 - 6, 2016
5) If a large truck with a mass of 10,000 kilograms traveling at 40 meters/second collides head-on with a car with a mass of 2,000 kilograms traveling 40 meters/second, how much of a greater impact force will the car experience compared to what the truck will experience and why? Assume no friction and air resistance.
6) Which would be more damaging: driving into a massive concrete wall, or driving at the same speed into a head-on collision with an identical car traveling toward you at the same speed? Why?

4. Physics Team Think-a-thon
Laws of Motion and Friction October 4 - 6, 2016
7) The brakes are slammed on a speeding truck with mass of 10,000 kilograms and it skids to a stop in 200 meters. If the truck were heavily loaded so it had twice the total mass, of 20,000 kilograms, the skidding distance would theoretically be:
a) the same
b) 1½ times as far
c) twice as far
d) four times as far
e) need more information
Why?
8) Susie holds the book stationary against the wall with the vector of her force as shown. Friction on the book by the wall acts
a) upward
b) downward
c) sideways
d) circular