Question

a block of mass 1500 g is moving with speed of 30 m/s. A force of 12 N is applied in the direction of motion for 3 sec. The speed of the block after 3 sec will bel​

Answer 1

Given:-

Mass of the block=1500g

=>1500/1000

=>1.5kg

Initial velocity(u)=30m/s

Force(F)=12N

Time=3s

To find:-

Velocity of the block after 3s i..e final velocity(v)

Solution:-

By,Newton's 2nd law of motion,we know that---

=>F=m(v-u)/t

=>12=1.5(v-30)/3

=>12×3=1.5v-45

=>36=1.5v-45

=>36+45=1.5v

=>81=1.5v

=>v=81/1.5

=>v=54m/s

Thus,velocity of the block after 3s is 54m/s.

Answer 2

Given:-

Mass of the block=1500g

=>1500/1000

=>1.5kg

Initial velocity(u)=30m/s

Force(F)=12N

Time=3s

To find:-

Velocity of the block after 3s i..e final velocity(v)

Solution:-

By,Newton's 2nd law of motion,we know that---

=>F=m(v-u)/t

=>12=1.5(v-30)/3

=>12×3=1.5v-45

=>36=1.5v-45

=>36+45=1.5v

=>81=1.5v

=>v=81/1.5

=>v=54m/s