Question

6. A force of 10 N acts on a body of mass 2 kg for
3 s, initially at rest. Calculate : (i) the velocity
acquired by the body, and (ii) change in momentum
of the body.​

Answer 1

Given that

Force=10N

Mass=2kg

time=3s

initial velocity =0m/s

final velocity =?

F=ma

a=f/m

a=10/2

a=5m/s2

final velocity

v=u+at

v=0+5×3

v=15m/s

momentum =mv

2×15

=30kgm/s

Answer 2

Answer:

(I) F = ma

F = m(v)/s

[acceleration = velocity/time]

10N = 2kg × v/3s

(10N×3s)/2kg = v

15m/s = velocity

(II) Initial momentum = mass×initial velocity

= m×u

= 2kg × 0m/s

= 0 kgm/s

Final momentum = mass × final velocity

= m×v

= 2kg × 15m/s

= 30 kgm/s

Change in momentum = ∆P = (m×v)-(m×u)

= 30 - 0

= 30 kgm/s