- #1
Nito
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Homework Statement
A ball of mass 0.150 kg is dropped from rest from a
height of 1.25 m. It rebounds from the floor to reach a
height of 0.960 m. What impulse was given to the ball
by the floor?
Homework Equations
Δmv/t =I
vf^2=vo^2 +2aΔy
The Attempt at a Solution
mghi = mghf +1/2mvf^2
vf = 2.38m/s
0.150kg x (2.38-0) = 0.35 Kg m/s
But this did not work. What the answer key did was use kinematics equations to find the velocity before the ball hit the ground and then found the velocity when the ball reached the height 0.960m. They then did change in velocity x mass to find the impulse.
Essentially, I don't see why using the conservation of energy equation to find the change in velocity is wrong. Why does this not work?