An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms^-1 to 8 ms^-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.
Laws of Motion
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Question

An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms^-1 to 8 ms^-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.

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KnowledgeBoat · Accepted Answer

Given,

Mass of the object (m) = 100 kg

Initial velocity (u) = 5 ms^-1

Final velocity (v) = 8 ms^-1

Time period (t) = 6 s

Now, initial momentum (m × u) = 100 × 5 = 500 kgms^-1

Final momentum (m × v) = 100 × 8 = 800 kgms^-1

Hence, Initial momentum = 500 kgms^-1 and final momentum = 800 kgms^-1

As per the first equation of motion,

a = $\dfrac{\text{v - u}}{\text{t}}$

Substituting we get,

a = $\dfrac{8-5}{6}$ = 0.5 ms^-2

We know, Force = mass x acceleration

Substituting we get,

F = 100 x 0.5 = 50 N

Hence, magnitude of the force = 50 N