A ball is dropped from rest from a hot air balloon. It hits the ground 15 seconds later. a. Calculate the speed with which it hits the ground. i. V = U + AT V = 0 + 9.8*15 V = 147 m/s b. Find the height from which the ball was dropped. i. S = 0.5(U + V)T^2 S = 0.5(147)15^2 S = 16537.5 ii. V^2 = U^2 + 2AS S = 1102.5 metres
Answer a is fully correct but only ii is correct for b. I really want to know why the first one didn’t work. I genuinely can't see what I've done wrong and I want to know how I can prevent this happening during a test.
A ball is dropped from rest from a hot air balloon. It hits the ground 15 seconds later. a. Calculate the speed with which it hits the ground. i. V = U + AT V = 0 + 9.8*15 V = 147 m/s b. Find the height from which the ball was dropped. i. S = 0.5(U + V)T^2 S = 0.5(147)15^2 S = 16537.5 ii. V^2 = U^2 + 2AS S = 1102.5 metres
Answer a is fully correct but only ii is correct for b. I really want to know why the first one didn’t work. I genuinely can't see what I've done wrong and I want to know how I can prevent this happening during a test.
For b i, you squared 15 but you’re not supposed to. If you don’t square 15 you get 1102.5m