Speed of the motorbike = 72 km/hr = 20 m/s
Speed of police jeep = 108 km/hr = 30 m/s
Let the jeep catch up with the bike after t seconds.
Therefore,
30 t = 20 ( t + 10)
t = 20 sec
Distance travelled by jeep in 20 sec,
s =30 x 20 = 600 m
Here,
Frequency,
revolutions per second
We know,
Angular frequency, =
= 20 rad sec-1
When a person is at rest with respect to ground, the rain is coming to him at an angle 30o with the vertical, i.e., along OB.
As the person moves along OA with velocity 10 m/s, the relative velocity of rain w.r.t person is along OC as shown in fig. below.
Here, o
Therefore, velocity of rain w.r.t ground =
Velocity of person w.r.t. ground =
Velocity of rain w.r.t person =
a)
b)
In
= 10/ (1/) = 10
Therefore, velocity of train w.r.t person = 10 m/s