Question

A force of 25 N acts on a body at rest for 0.2seconds
and a force of 70 N acts for the next 0.1seconds in
opposite direction. If the final velocity of the
body is 5ms ,the mass of the body is
1)1kg 2) 2kg 3) 0.8kg 4) 0.48​

Answer 1

Answer:

mass = kg/m squares

Explanation:

you can solve this I'm telling you formula

Answer 2

Answer:

Let the mass of the body be m.

Case:1

Force of 25N acts on the body for 0.2s

We know that F=ma

F=ma

F=m[(v-u)/t]

25=m[(v-0)/0.2]

5=mv

v=5/m

This velocity acts as initial velocity for the next case.

Case:2

Force of 70N acts for the next 0.1s in Opposite direction.

Initial velocity=5/m

Final velocity=-5 {negative as because in opposite direction}

Force=-70N

F=ma

-70=m[(-5-5/m)/0.1]

-7=m[-5-5/m]

-7=-5m-5

-2=-5m

m=2/5=0.4Kg

Hence mass of the body is 0.4

Hope you understood the question