Calculating Work Done on a Basketball Dropped from 5m

[Fatima Hasan]

Homework Statement

A basketball with a mass of 0.56 kg drops from a height of 5 m and bounces off the floor back up to a maximum height of 4.3 m .Find the work done on the ball by the ground during the time the ball is in contact with it.

Homework Equations

W = - Δ Ug
Ug = mgh

The Attempt at a Solution

ΔUg = mghƒ - mghι
= 0.56*10*4.3 - 0.56*10*5 = - 3.92 J
W= - Ug = 3.92 J
Can somebody check my answer please ?
Thanks for your help.

 

[PhanthomJay]

The magnitude of the work done by the ground is correct, however you have a signage error because you incorrectly applied the equation for work done by the ground. The formula you used is for the work done by gravity. What equation should you be using for work done by the ground, which is work done by a non conservative force?