Question

A train is moving with velocity 20m/s, on this dust is falling at a rate of 50kg/minute. Find the extra force required to move this train with constant velocity.​

Answer 1

GiveN :

A train is moving with the velocity 20 m/s & on the same train dust is falling at the rate of 50 kg/min.

That is,

• Velocity, v = 20 m/s

However, we also know that,

↬ F = m × a

Now as acceleration isn't given we'll have to replace the value of a with $\sf \dfrac{dv}{dt}$.

Now the formula becomes :

$\longrightarrow\sf F = m \times\dfrac{dv}{dt}$

$\longrightarrow\sf F = v \times\dfrac{dm}{dt}$

Substituting the values :

$\longrightarrow\sf F = 20 \times\dfrac{50}{60}$

$\longrightarrow\sf F = \dfrac{50}{3}$

$\longrightarrow \large{ \boxed{\frak{ F = 16.66 \: N.}}}$

$\therefore$The extra force required to move this train with constant velocity is 16.66 N.

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$\;\;\;\;\;\;\large{\underline{\underline{\frak{More\: to \: know :}}}}$

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• As in the above answer we've used the eqn that F = m × a

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• This eqn is given by the Newton's second law.

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• Generally, it means that the mass a body has, the more force you need to accelerate it.