Question

A body of mass 2 kg moving on a horizontal surface
with an initial velocity of 4 m/s comes to rest after
2 s. If one wants to keep this body moving on the
same surface with a velocity of 4 m/s, the force
required is :-
(1) 8 N
(2) 4 N
(3) Zero
(4) 2 N​

Answer 1

Answer:

We need to find force.

Now,

F = ma

m = 2kg

u (initial velocity) = 4m/s

v (final velocity) = 0m/s, as the body comes to rest

t = 4s

a = (v-u)/t = (0-4)/4 = -4/4 = -1m/s²

∴ F required to make body come to a stop = -1 × 2 = -2 N

To oppose this force and to keep the body moving, we need a force of 2N.

(4) 2 N is the correct answer.

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