Question

A train consisting of 40 wagons of 20 ton each is pulled by an engine with velocity of 20m/s.The power delivered by the engine is 160kW.The frictional force offered per ton of the trian is
1.)1N 2.)5N 3.)10N 4.)20N
3rd option is correct.

Answer 1

Explanation:

Given :

Mass of each wagon = 20 ton

No. of wagons = 40

power = 160kw

To find :

The frictional force offered per ton of the trian is

Solution

Mass of each wagon = 20 ton

No. of wagons = 40

total mass = 40 * 20 = 800

Let us assume that frictional Force is x

power = Force * velocity

total frictional Force = 800 * x

velocity = 20m/sec

$\bold{16 \times 10 {}^{4}w \: = x \times 800 \times 20 }$

$\bold{16 \times 10}^{4} = 16 \times 10 {}^{3} \times x$

$\huge \bold{ \frac{16 \times 10 {}^{4} }{16 \times 10 {}^{3}} }$

$\huge \bold\red{10 \: N}$

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