What Is the Person's Velocity After the First 25 cm of the Chin-Up?

[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?

 

[Pyrrhus]

Try using W = \Delta K

 

[Sirus]

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