Answer:
Gravity ( gravity , weight, traction force) is the force acting on any body on or near the surface of the celestial body directed at its center. Gravity, that is, the force with which the earth , moon , planets, and other celestial bodies or their systems act on other bodies, is theoretically exercised at any distance, but is practically examined on the surface of these bodies as well as at short distances.
Answer:
a) The velocity of the car is 7.02 m/s and the car is approaching to the police car as the frequency of the police car is increasing.
b) The frequency is 1404.08 Hz
Explanation:
If the police car is a stationary source, the frequency is:
(eq. 1)
fs = frequency of police car = 1200 Hz
fa = frequency of moving car as listener
v = speed of sound of air
vc = speed of moving car
If the police car is a stationary observer, the frequency is:
(eq. 2)
Now,
fL = frequecy police car receives
fs = frequency police car as observer
a) The velocity of car is from eq. 2:

b) Substitute eq. 1 in eq. 2:

A. Equal and opposite
For every action, there is an equal and opposite reaction
D.6.22N. because .42kg * 14.8m/s=6.22 N[meaning newtons}.
Answer:
Because the light reflects multiple times until it gets to the Cassegrain focus.
Explanation:
The Cassegrain design can be seen in a reflecting telescope. In this type of design the light is collected by a concave mirror, and then intercepted by a secondary convex mirror, and sends it down to a central opening in the primary mirror (concave mirror), in which a detector is placed (Cassegrain focus)
Since, the light is reflected many times due to Cassegrain design, that leads to shorter telescopes.