Question

A constant force of magnitude 20 N acts on a body of mass 2 kg, initially at rest, for 2 seconds. What will be the velocity of the body after (a) 1 second from start? (b) 3 seconds from start?

Answer 1

Force = 20 N
mass = 2 kg
time = 2 sec

F = ma
20 = 2×a
a = 10 m/s

(a) u = 0
a = 10
t = 1 sec

v = u+at
v = 0 + 10
v = 10 m/s

(b) as this force acts only for 2 seconds, therefore the velocity after 2 sec i.e at 3sec will equals to the velocity at the end of 2sec

u = 0
t = 2
a = 10

v = u + at
v = 0+ (10×2)
v = 20 m/s
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