Question

Question 1 (2d motion) A ball is thrown from a cliff that is 20 meters high at a target below 30 meters away. The ball reaches the target in a time of exactly 1.5 seconds. nitial velocity 1.5 s 20 m 30 m a. What is the initial velocity of the ball in cartesian coordinates? b. What is the initial velocity of the ball in polar coordinates?

Answer 1

'X' component of velocity = v sin theta 'Y' component of velocity = v cos theta t = 1.5 s (V sin theta) t = 30 (in X direction) 1.5 V sin theta = 30 equation (i) V sin theta = 20 in 'Y' direction s = ut + 1/2 at^2 20 = (V cos theta)t + 1/2 (9.81)t^2 20 = (1.5V cos theta) + 1/2 (9.81) (1.5)^2 equation (ii) V cos theta = 5.97 In Cartesian coordinates V^vector = 20i^^- 5.97j^^m/s In polar coordinates V^vector = 20.87 angle -16.62 m/s