Question

"A football of mass 140 grams falls to the ground from a height of 1.7metres. Ignoring air resistance, calculate the peed of the ball as it hits the ground:" Took me ages to remember I can use lost in potential energy = gain in Kinetic energy. In the end, I got 5.83 m/s, just wanted to know if this is correct

Answer 1

Yes you are right.

Answer 2

Yes that is correct.
The quickest way to solve the problem is with the equation:
velocity = root(2*height*gravity) or v=root(2gh).
This is a result of the method you used - the equation comes from rearranging
E(potential) = mass*gravity*height = E(kinetic) = 0.5*mass*v^2

Answer 3

thnx