Question

The minute hand of a wall clock is 10 cm long . find its displacement and the distance covered from 10 am to 10:30 am .
A train goes from town A to town B with a uniform speed of 40km/hr and returns back to A with a speed of 60km/hr .calculate the average speed and the average velocity for the entire journey

Answer 1

the displacement of the minute hand =  πr cm
average speed = 50 km/hr
 

Answer 2

Minute hand will works as radius and make a circle of radius 10cm
Displacement is given by=2r=20cm
Distance is given by =πr=22/7x10=3.14x10=31.4cm
first distance covered by speed=40km/hr
second distance covered by speed=60km/hr
Average is given by=s1+s2
                                 2
60+40    =50km/hr
2