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.

3 answers

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.