Question

11) 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.(3)
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Answer 1

Answer:

Initial velocity of the object, u = 5 m/s

Final velocity of the object, v = 8 m/s

Mass of the object, m = 100 kg

Time take by the object to accelerate, t = 6 s

Initial momentum = mu = 100 — 5 = 500 kg m sˆ’1

Final momentum = mv = 100 — 8 = 800 kg m sˆ’1

Force exerted on the object, F = mv – mu / t

= m (v-u) / t

= 800 – 500

= 300 / 6

= 50 N

Initial momentum of the object is 500 kg m sˆ’1.

Final momentum of the object is 800 kg m sˆ’1.

Force exerted on the object is 50 N.

Answer 2

Answer:

p=mv

initial momentum=100×5=500 kgm/s

final momentum=100×8=800kgm/s

F=m(v-u)/t

F=100(8-5)/6

F=100(3)/6

F=100/2

F=50kg ms-2