Question

A force of 15 N acts on a body of mass 5 kg for 2s what is the change in velocity of a body?
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Answer 1

Answer:

The answer is 6.

Explanation:

Here

          Force is 15N

          Mass is 5kg

          Time is 2 seconds

          Velocity =?

We have,

              F=mg

         or, 15= 5*g

         or, g= 15/5

  therefore, accleration(g) = 3m/s sq.

Then we have,

                    distance(s)= ut+(1/2)gt square

                               or, s= 0*2 +(1/2) 3*2 square[ since, initial velocity(u)=0]

                               or, s= 0+ 0.5*3*4

         therefore, s= 6m

Again

          We know, s= [(u+v)/2] *t

                      or,2s=[0+v]

                       or,2*6=2v

therefore, v= 6m/s

Hello, My name is Shandeh Tharu from NEPAL. I am studying in grade 10 now.

Answer 2

Answer:

Δv = 6 m/s

Explanation:

Given, force(F) = 15 N, Mass(m) = 5 kg, Time(t) = 2 s

to find, Change in velocity(Δv) = v - u

We can use $v-u=at$...(1) formulae for finding Δv.

but first of all we need to find acceleration(a), to find that we use $F = ma$

here, F = 15 N, m = 5 kg

so, $a = \frac{15}{5}= 3m/s^2$....(2)

Now, substituting (2) in (1) we get,

$v-u =3m/s^2(2s)$

therefore, Δv = 6 m/s

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