Physics
posted by Tyners .
a barrel of oil at rest has a mass of 65kg it is rolled down a 1.2m ramp. Due to constant force exerted on it, the barrel reaches a velocity of 4.2 m/s upon leaving the ramp. Find the constant force on the barrel while it is on the ramp?
Help please.

It is unclear whether the barrel is rolling or sliding. If one assumes sliding down a frictionless ramp,
F=ma
where vf^2=2a*4.2 or a=vf^2/8.4
solve for f.
Now, if rolling, come back and say so, it is more complicated. 
rolling down a ramp not sliding

Now if it is rolling, the filled barrel has a moment of inertia of 1/2 Mr^2
The angular velocity at the bottom must be w=Vf/r
KE at bottom=PE at top
1/2 I w^2+ 1/2 m vf^2=mgh
so solve for h.
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