Question

3. A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a statement about the direction of the velocity and the acceleration as the ball is coming down. (1 mark) a) Both its velocity and its acceleration point upward b) Its velocity points downwards and its acceleration points upwards c) Its velocity points upwards and its acceleration points downwards d) Both its velocity and its acceleration point downwards. 4. A man stands on a bridge 7.0 m above a river. He tosses a rock vertically upwards at 12 m/s. The rock sails upwards, reaches a maximum height and then returns downwards, splashing into the river. a) What is the maximum height that that rock attains? (3 marks) b) How long does it take to reach its maximum height? (3 marks) c) How fast is the rock traveling upon impact in the river? (3 marks)

Answer 1

@ velocity (clown) acceleration & (down) [always] a (d)~ کہ اما) fu=12m/s 7m &= ut + X at h = X2 (t) Ixio xt² 2 12t 157² 0 cal v2=ú tras ㅕ = ) (12)2 - 2x10h h=14472 2x10 7.2 m (6) Uz ut at >.o=12 12 -(0) t = 1.2 sec

be Ų let the Velocity of impact 4 so va = (12)2 - 2(10)(-7) a VI = Joey to =16.853 m/s