Answer:
It will take 50 seconds for the pebble to reach the height
Step-by-step explanation:
To calculate the time, simple substitute h(t) for 32,500
So we have
32,500 = 20,000 + 5t^2
5t^2 = 32,500-20,000
5t^2 = 12500
t^2 = 12500/5
t^2 = 2500
t = square root of 2500
t = 50 seconds
