Question

1. In the given figure shown body is moving with the velocity of 2m/s. the work done by 5 N force till body comes to rest is :
a) -15/2 Joule
b) 9/2 Joule
c) -9/2 Joule
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Answer 1

Answer:

b. 9/2 joule , this is answer

Answer 2

Work done by the 5 N force till body comes to rest is 8 joule.

Explanation:

Net force which is stopping the body to take it to rest is

            ⇒ 5 - 3 = 2 N

We know that

                  ⇒ F = m x a

                 ⇒ a = $\frac{F}{m}$

                 ⇒ a = $\frac{2}{2}$

                  ⇒ a = 1 m/$s^{2}$

Also,        

                   ⇒ a =  $\frac{s}{t}$

                  ⇒ t = $\frac{s}{d}$

                  ⇒ t = 2 sec.

         So,

            ⇒ v =  $\frac{d}{t}$

              ⇒ d = v x t

               ⇒ d = 4 m

Hence,

             ⇒ W = F x d

               ⇒ W = 2 x 4

                ⇒ W = 8 J.