I need help on how to understand and solve this problem:
A ball is thrown upward at a speed of 48 feet per second from the edge of a cliff 432 feet above ground. Find its height above ground t seconds later.
When does it reach its maximum height?
When does it hit the ground?
(Note: Give the upward direction as positive, physics tells us that the acceleration of the ball is -32 feet per .
....... If the acceleration is a then the speed after t seconds is v(t).
....... If the acceleration is a then the distance after t seconds is d(t).
With your problem:
....... And therefore the height over ground is calculated by:
The graph of d(t) is a parabola opening down. So the highest point is reached at the vertex of the parabola which occurs after t = 1.5 s:
The ball hits the ground if the height is zero:
....... Solve for t. You'll get 2 solutions but one of them isn't very plausible. I've got 6.91 s.