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.
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.
Solution:
Mass of object, $\mathrm{m}=100 \mathrm{~kg}$; initial velocity,
$\mathrm{u}=5 \mathrm{~ms}^{-1} ;$ final velocity, $\mathrm{v}=8 \mathrm{~ms}^{-1} ;$ time,
$\mathrm{t}=6 \mathrm{~s}$
Initial momentum $=\mathrm{mu}=100 \times 5=500 \mathrm{Ns}$
Final momentum $=\mathrm{mv}=100 \times 8=800 \mathrm{Ns}$
Force exerted on the object
$\mathrm{F}=\frac{\mathrm{mv}-\mathrm{mu}}{\mathrm{t}}=\frac{800-500}{6}=\frac{300}{6}=50 \mathrm{~N}$
Mass of object, $\mathrm{m}=100 \mathrm{~kg}$; initial velocity,
$\mathrm{u}=5 \mathrm{~ms}^{-1} ;$ final velocity, $\mathrm{v}=8 \mathrm{~ms}^{-1} ;$ time,
$\mathrm{t}=6 \mathrm{~s}$
Initial momentum $=\mathrm{mu}=100 \times 5=500 \mathrm{Ns}$
Final momentum $=\mathrm{mv}=100 \times 8=800 \mathrm{Ns}$
Force exerted on the object
$\mathrm{F}=\frac{\mathrm{mv}-\mathrm{mu}}{\mathrm{t}}=\frac{800-500}{6}=\frac{300}{6}=50 \mathrm{~N}$
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