Question

A barrel is rolled up a ramp of 6m long, The barrel weighs 400N and is raised through a height of 1.5m. If a force of 120N is applied parallel to the inclined plane, calculate.

1. The useful work done.    
2. The work input.       
3. The frictional force against motion of the barrel.            
4. Efficiency of the inclined plane.  

Answer 1

1. P.e = mgh=400N × 1.5m
                =600J
2. F × d=120N × 6m
           =720J
3. w_Fr =(720−600)J
         = 120N =20N
              6m
4. Work output ×100 =  ⁶⁰⁰/₇₂₀ ×100
    Work put                
                          =83.33%

Answer 2

¹.p,e=mgh=400N*1.5m
=600J