Question

A body of mass 5 kg is moving with speed 144 km/h then its momentum is 2x10^x gr-cm/sec then find 'x'

Answer 1

Given that,

Mass of a body, m = 5 kg

Speed of body, v = 144 km/h

Momentum, $p=2\times 10^x\ g-cm/s$

To find,

The value of x

Solution,

The product of mass and velocity equals momentum.

Here, momentum is given in g-cm/s. We need to convert mass to grams and velocity to cm/s

5 kg = 5000 g

144 km/h = 4000 cm/s

So,

$p=mv\\\\2\times 10^x\ g-cm/s=5000\ g\times 4000\ cm/s$

or

$2\times 10^x=5000\times 2\times 2000\\\\2\times 10^x=2\times (5000\times 2000)\\\\2\times 10^x=2\times 10000\\\\2\times 10^x=2\times 10^4$

Now comparing both sides, we get the value of x equals 4.