Question

A vehicle is travelling at a speed of 90 km/hr. Express the speed in its S.I unit.​

Answer 1

Answer:

25m/s

Explanation:

m/s is si unit so

To convert km/h to m/s, directly multiply the given value of speed by the fraction 5/18

so 5/18*90=25

hence 25m/s is correct answer

Answer 2

A train is travelling at a speed of 90 km h-1. Brakes are applied so as to produce a uniform acceleration of –0.5 ms-2. Find how far the train will go before it is brought to rest.

Given that

Initial velocity (u) = 90 km/hour = 25 m.s-1

Terminal velocity (v) = 0 m.s-1

Acceleration (a) = -0.5 m.s-2

Find out

How far the train will go before it is brought to rest

Formula

As per the third equation of motion, v2-u2=2as

Therefore,

The distance travelled by train (s) =(v2-u2)/2a

On substituting the known values we get

s = (02-252)/2(-0.5) meters

= 625 meters