# Energy - Work/velocity problem

1. Sep 28, 2004

### Blckshdwdragon

Original Question: A person doing a chin-up weighs 700N exclusive of the arms. During the first 25.0 cm of the lift, each arm exerts an upward force of 355N on the torso. If the upward movement starts from rest, what is the persons velocity at the point.

some work:
700-2(355) = 10 N
W = 25 cm *10 N
.25M*10N= 2.5 J
(Mass ~ 700N = 9.8[M] )
A = 2.5 / 71.4
=.035 m/s

My question: so what do I do now with this .035 m/s?

2. Sep 28, 2004

### Pyrrhus

Try using $$W = \Delta K$$

3. Sep 28, 2004

### Sirus

You could also find acceleration using $F_{net}=ma$ then use kinematic formulas to find final velocity.