Question

a constant force F is applied to. body of mass m moving with initial velocity u .if after the bosy undergoes a displacement Sits velocity becomes v then the total work done is​

Answer 1

a constant force F is applied to the body of mass m moves with Initial velocity u. after displacement, S its velocity becomes v then we have to find total workdone by body.

according to work-energy theorem,

change in kinetic energy of body = workdone by body.

or, final kinetic energy - initial kinetic energy = W

or, 1/2 mv² - 1/2 mu² = W

or, 1/2 m(v² - u²) = W .... (1)

also workdone = force applied on body × displacement along applied force.

i.e., W = F × S ......(1)

from equations (1) and (2),

workdone , W = F × S = 1/2 m(v² - u²)

Answer 2

Answer:

Work done=$m\times \frac{v-u}{t}\times s$

Explanation:

Since a constant force is applied that means acceleration is also remains constant.

force $F=m\times a$.........................(1)

where m = mass , a = acceleration

we know that acceleration is defined as change in velocity with respect to time.

$a = \frac{v-u}{t}$..............................(2)

v=final velocity , u = initial velocity , t = time

we know that

work done $w = force\times displacement$

using (1) and (2) we get

So, w=$m\times \frac{v-u}{t}\times s$

Here s = displacement.