Question

A cyclist covers a distance of 100m in 20s calculate the speed of the cyclist in (i) m/s
(ii) km/h

Answer 1

S=100m=0.1km

Time taken,t=20s=20/3600h.

Speed in m/s is d/t=

100/20m/s

=5m/s

Speed,v in km/h is distance/ time

=0.1/20/3600 km/h

=180km/h.

Thank you!

Answer 2

Answer:

The speed of the cyclist is 5m/s or 18km/h.

Explanation:

Given that,

A cyclist covers a distance of 100m in a time of 20 seconds.

We are required to calculate the speed of cycle in both the units m/s and km/h.

We know that,

Speed is the ratio of distance to time.Hence,we can write it as follows

$v=\frac{d}{t}$

Substituting the value of distance and time in above relation,we get

$v=\frac{100m}{20s}=5m/s$

Hence,The speed of the cyclist is 5m/s.To convert it into km/h,we shall use the following conversions-

$1km=1000m= > 1m=10^{-3}km\\1hr=3600s= > 1s=\frac{1}{3600} hr$

Substituting these values in our obtained speed we get the speed as

$v=5\times\frac{10^{-3}km}{\frac{1}{3600}h } =18km/h$

Therefore,the speed of the cyclist is 5m/s or 18km/h.

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