Assignment:
1. Problem 1: Kintematics in 2-D
A stunt person drives a car at a speed of 20m/s off a 30m high cliff. The road leading to the cliff is inclined upward at an angle of 20?.
(a) List your known and unknown variables.
(b) Draw a pictorial representation with all relevant information presented on it.
(c) How long is the car in the air for? Express this time symbolically.
(d) Sensemaking: Check the units you should get form your symbolic time equation, do they make sense?
(e) Find the numeric time value.
(f) How far from the base of the cliff does the car land? Express this distance symbolically.
(g) Sensemaking: What would you expect the distance to be if the incline was horizontal (θ = 0?)?
If the incline was vertical (θ = 90?)? Does your equation from part 1f match your intuitions?
(h) Find the numerical distance.
(i) What is the cars impact speed? Express this speed symbolically.
(j) Find the numerical speed.
(k) Sensemaking: Is the speed you found a vector or scalar? Which should it be and why?
2. Problem 2: Free Body Diagrams
Draw a free body diagram for each of the situations below:
(a) A cat is sitting on a window sill.
(b) An ice hockey puck glides across frictionless ice.
(c) Your physics textbook is sliding across the table.
(d) A rocket is being launched straight up. Air resistance is not negligible.
(e) Your friend went for a loop-the-loop ride at the amusement park. Her car is upside down at the top of the loop.
(f) A bag of groceries is on the seat of your car as you stop for a stop light. The bag does not slide.
Draw a free-body diagram for the bag.