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.
3 s, initially at rest. Calculate : (i) the velocity
acquired by the body, and (ii) change in momentum
of the body.
Answers & Comments
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:
(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