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.:
Answer:For a perfectly elastic collision, the final velocities of the carts will each be 1/2 the velocity of the initial velocity of the moving cart. For a perfectly inelastic collision, the final velocity of the cart system will be 1/2 the initial velocity of the moving cart.
Explanation:
Approximately 100-120 wolves
Answer:
Efficiency = 80%
Explanation:
Given the following data;
Work output = 240 N
Work Input = 300 N
To find the mechanical efficiency of a machine;
Substituting into the equation, we have;
Efficiency = 80%
Therefore, the mechanical efficiency of the machine is 80 percent.
