The question is not well presented.
There is ______ shift in sound frequency for observers towards whom the source is approaching.
Answer:
The gap should be filled with an apparent upward
Explanation:
The Doppler effect (also referred to as the Doppler shift) is the difference in frequency of a wave when related to an observer who has a relative movement to the wave source
The Doppler effect can be observed to occur with all types of waves - most notably water waves, sound waves, and light waves
The Doppler effect describes sound as an effect which is produced from a moving source of wave.
According to the Doppler effect;
When the source of waves in which there is an apparent upward shift in frequency for observers towards whom the source is approaching.
Answer:
c) is negative
Explanation:
As we know that work done by a force is the product of force and displacement vector.
W= F.d
F= Force
d= displacement
The work done by friction force always negative because it try to oppose the motion and act opposite to the direction of displacement.So the work done by air resistance is negative.
c) is negative
Explanation:
Given that,
Mass of the car, m = 710 kg
Speed of the car, v = 23 m/s
Drag force, F = 500 N
(a) Let P is the power is required from the car's engine to drive the car on the level ground. Power is given by :

(b) Let P is the power is required from the car's engine to drive the car on up a hill with a slope of 2 degrees.
At this slope, force will be, 
Total force will be :

Power is given by :

or
P = 17 kW
Answer:
8.2N
Explanation:
I took the test and got it right :)
Mass, weight. Mass is independent of the object’s location, whereas weight is not.