Answer:
8 minutes
Explanation:
Part of the question is missing. Complete question is:
<em>Simpson drives his car 144 km with an average velocity of 24 m/s toward the east. How much time would Simpson save by increasing his average velocity to 26m/s East?</em>
Solution:
First of all, we have to calculate the time it takes for Simpson to complete the drive moving at the initial velocity, 24 m/s. We can use the formula:

where
is the displacement
is the velocity
Substituting,

While driving at 26 m/s, the time taken will be

So, Simpson will save 8 minutes.
if the velocity of the car reduces from 70km/h to 50km/h then the speed of the car will be equal to the speed of the lorry...
thus the relative velocity will be 0
Answer:
Explanation:
We shall apply concept of Doppler's effect of apparent frequency to this problem . Here observer is moving sometimes towards and sometimes away from the source . When observer moves towards the source , apparent frequency is more than real frequency and when the observer moves away from the source , apparent frequency is less than real frequency . The apparent frequency depends upon velocity of observer . The formula for apparent frequency when observer is going away is as follows .
f = f₀ ( V - v₀ ) / V , f is apparent , f₀ is real frequency , V is velocity of sound and v is velocity of observer .
f will be lowest when v₀ is highest .
velocity of observer is highest when he is at the equilibrium position or at middle point .
So apparent frequency is lowest when observer is at the middle point and going away from the source while swinging to and from before the source of sound .
No velocity will not be changed
Why?
According to Newtons 1st law the velocity of a moving object remains unchanged unless a external force affect that.