Answer:9.75 m/s
Explanation:
Given
Length of ladder 
Foot the ladder is moving away with speed of 
From diagram
------1
at 


Now differentiating equation 1 w.r.t time




negative indicates distance is decreasing with time
Answer:
the speed of the tip of a blade 10 s after the fan is turned off is 16.889 m/s.
Explanation:
Given;
diameter of the ceiling fan, d = 90 cm = 0.9 m
angular speed of the fan, ω = 64 rpm
time taken for the fan to stop, t = 28 s
The distance traveled by the ceiling fan when it comes to a stop is calculated as;

The speed of the tip of a blade 10 s after the fan is turned off is calculated as;

Therefore, the speed of the tip of a blade 10 s after the fan is turned off is 16.889 m/s.
Answer:
Frequency of the light will be equal to 
Explanation:
We have given wavelength of the light 
Velocity of light is equal to 
We have to find the frequency of light
We know that velocity is equal to
, here
is wavelength and f is frequency of light
So frequency of light will be equal to 
So frequency of the light will be equal to 
There is 4000 balls in the earth of the world why is that so hard for you