PHysics Projectile Motion

Question

A car is parked on a cliff overlooking the ocean on an incline that makes an angle of 17 degrees below the horizontal. The negligent driver leaves the car in neutral, and the emergency brakes are defective. The car rolls from rest down the incline with a constant acceleration of 4.8 m/s 2 and travels 43 m to the edge of the cliff. The cliff is 30 m above the ocean. (a)How long is the car in the air? The acceleration of gravity is 9.81 m/s 2 . Answer in units of s.

(b) What is the car’s position relative to the base of the cliff when the car lands in the ocean? Answer in units of m.

Answer 1

1) Use v² = 2ad in order to find the the launch velocity, v₀. (Note that d is distance along incline)

2) You find the time in the air by solving y-y₀ = v_y0t - (1/2)gt² for y - y₀ = -height of cliff (yes it's a quadratic and you use quadratic formula. v_y0 is v(part 1) sin(-17°)

3) The range is just R = v_x0t_air where v_x0 is v(part 1)cos(-17°) and t in the air is t (part 2)

Good luck!