# Homework Help: Maximum speed of a cylinder dropped on a spring

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1. Jul 14, 2016

### Rajveer97

1. The problem statement, all variables and given/known data
Cylinder A (mass = 5kg) is released from rest at a height h =100mm above a spring of stiffness k = 1.8 kN/m. Determine, (i) the maximum compression of the spring, (ii) the spring deflection when the cylinder’s velocity is a maximum, and, (iii) the maximum velocity of the cylinder

I just need to confirm part iii

2. Relevant equations
Ep=mgh
Ek=(1/2)mv^2
Es=(1/2)kx^2
F=kx

3. The attempt at a solution
For part (i) I got 0.106
(ii) 27.2mm
For (iii) I did Ep=Ek which gave me v=1.4. The correct answer is supposed to be 1.49, I feel my answer is similar is wrong but similar just by chance. I just don't fully understand the question, when will the speed be maximum, before or after deflection? I feel before but I'm unsure.

Thanks

2. Jul 14, 2016

### BvU

Hi,
You don't really specify what you did. Could there be a term missing in your 'doing'?

3. Jul 14, 2016

### Rajveer97

Well I meant I basically made gravitational potential energy equal kinetic energy and solved for v

4. Jul 14, 2016

### BvU

Es ?

5. Jul 14, 2016

### haruspex

What, roughly, is the cylinder's acceleration very shortly after hitting the spring?