Question

a block A,whose weight is 200 N ,is pulled up slowly on a slope of length 5 m by means of a constant force F(=150 N)as illustrated in figure (a)what is the work done by the force F in moving the block A ,5 m along the slope ?(b) by how much has the potential energy of the block A increased ?(c) account for the difference in work done by the force and the increase in potential energy of the block.

Answer 1

(A) work done = force×displacement
                       =150    ×5 
                       =750 j
(B) p.e at ground =mgh
                             =20×10×0
                             =0
(c) difference between them =750-0=  750

Answer 2

Answer:(a) 750N

(b)600Watt

(c)150

Explanation:(a)F=150newton

S=5m

Work done =F*s

=>150*5=750N

(b)force /weight =mass*acceleration due to gravity

=>200=m*10

=>m=200/10=>20kg

Now, potential energy at ground =m*g*h

=>20*10*0=>0

Potential energy at B=m*g*h

=>20*10*3=>600Watt

Therefore, increase in potential energy =600-0=600Watt

(c)Difference =750-600=150