Question
on the physics content of your answer as well as on its structure, completeness and mathematical correctness. Remember, as with everything, neatness counts. 1. A student stands at the edge of a cliff as shown in figure 1 that is 50.0 m above a flat, horizontal beach and throws a stone horizontally over the edge with a speed of 18.0 m/s. h= 50.0 m g Fig.1: Projectile motion (a) What are the components of the initial velocity? (b) Write the equations for the x - and y - components of the velocity of the stone with time. (c) How long after being released does the stone strike the beach below the cliff? (d) With what speed and angle oßimpact does the stone land? 2. A projectile is fired with an initial speed of 60.0 m/s at an angle of 30.0
Explanation / Answer
(A) v0x = 18 m/s , v0y = 0
(B) vx = 18 m/s , v0y = - 9.8 t
(c) yf - yi = v0y t + ay t^2 /2
0 - 50 = 0 - 9.8 t^2 / 2
t = 3.19 sec
(d) vy = 9.8 x 3.19 = 31.3 m/s
Speed = sqrt(18^2 + 31.3^2) = 36.1 m/s
