Answer:
A) 1568.60 Hz
B) 1437.15 Hz
Explanation:
This change is frequency happens due to doppler effect
The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source

where
C = the propagation speed of waves in the medium;
Vr= is the speed of the receiver relative to the medium,(added to C, if the receiver is moving towards the source, subtracted if the receiver is moving away from the source;
Vs= the speed of the source relative to the medium, added to C, if the source is moving away from the receiver, subtracted if the source is moving towards the receiver.
A) Here the Source is moving towards the receiver(C-Vs)
and the receiver is standing still (Vr=0) therefore the observed frequency should get higher

B)Here the Source is moving away the receiver(C+Vs)
and the receiver is still not moving (Vr=0) therefore the observed frequency should be lesser

You can make sure there's no change in volume by keeping
your gas in a sealed jar with no leaks. Then you can play with
the temperature and the pressure all you want, and you'll know
that the volume is constant.
For 'ideal' gases,
(pressure) times (volume) is proportional to (temperature).
And if volume is constant, then
(pressure) is proportional to (temperature) .
So if you increase the temperature from 110K to 235K,
the pressure increases to (235/110) of where it started.
(400 kPa) x (235/110) = 854.55 kPa. (rounded)
Obviously, choice-b is the right one, but
I don't know where the .46 came from.
Answer:
The net force applied to the car is zero.
Explanation:
We are given that a car is moving to the left with constant velocity.
When the car moving with constant velocity
Then, the final velocity=Initial velocity
Change in velocity=Final velocity- initial velocity=0
When change in velocity is zero then , acceleration of car

When acceleration is zero then, By Newtons second law

The net force applied on the car will be zero.
Option C:The net force applied to the car is zero.