If a stone is dropped from rest and falls under gravity with an acceleration of 10m/s2, how long will it take before the stone is travelling at 25m/s? Can you show me how to work this out with math rules. I do not get it. Thanks
This is like the car problem.
At the start, t0, the stone has a speed of zero.
t0 = 0 m/s
The acceleration is (10 meters per second) per second, so after one second the speed is 10 m/s.
t1 = 10m/s
After another second, we add on another 10m/s to the speed
t2 = 20 m/s
At the third second, it's moving another 10m/s faster.
t3 = 30 m/s
Oops. We've overshot! We just wanted to get to 25m/s. But I'm sure you can figure where between 2 and 3 seconds it achieved that speed.