Answer:
a) The car was moving at a speed of 
b) The negative sign of
denotes that the observer is coming towards the police car which is the source of the sound.
c) 
Explanation:
Given:
- original frequency of the source,

- speed of the source,

- velocity of the obstacle car be,

- speed of sound,

- observed frequency,

<u>Using the equation from the Doppler's effect:</u>



a)
The car was moving at a speed of 
b)
The negative sign of
denotes that the observer is coming towards the police car which is the source of the sound.
c)
Now when, 
Then, 
Using the Doppler's eq.:


The mechanical advantage of a simple machine is the measure of its amplified force gain.
The mechanical advantage is defined as the force amplified by a machine to the force required to generate such output.

are the amplified force and applied force. We may also consider them as output and input force.
In the given question, the force given to the steering wheel is 50 N.
The output force produced by the steering wheel is 3750 N.
Hence the mechanical advantage will be-


[ans]
Answer:
The length of the solar day will get shorter.
Explanation:
- The blue planet Earth not only rotates around it's own axis but also rotates around the Sun and everyday it moves a little bit around the axis.
- Since the speed of the Earth's rotation on it's own axis and around the Sun is constant we don't feel the effects of the rotation.We can only feel the motion if the earth changes it's rotation speed.
- If by any means or chance the Earth stopped spinning (stopped rotation) then the atmosphere surrounding the Earth would be in motion and all the Earth's land would be scoured clean.
Explanation:
Pressure is the physical quantity having formula force per unit area.