Answer: V = 15 m/s
Explanation:
As stationary speed gun emits a microwave beam at 2.10*10^10Hz. It reflects off a car and returns 1030 Hz higher. The observed frequency the car will be experiencing will be addition of the two frequency. That is,
F = 2.1 × 10^10 + 1030 = 2.100000103×10^10Hz
Using doppler effect formula
F = C/ ( C - V) × f
Where
F = observed frequency
f = source frequency
C = speed of light = 3×10^8
V = speed of the car
Substitute all the parameters into the formula
2.100000103×10^10 = 3×10^8/(3×10^8 -V) × 2.1×10^10
2.100000103×10^10/2.1×10^10 = 3×108/(3×10^8 - V)
1.000000049 = 3×10^8/(3×10^8 - V)
Cross multiply
300000014.7 - 1.000000049V = 3×10^8
Collect the like terms
1.000000049V = 14.71429
Make V the subject of formula
V = 14.71429/1.000000049
V = 14.7 m/s
The speed of the car is 15 m/s approximately.
The amount of force an object has will change the velocity
Answer:
Where 
represent the force for each of the 5 cases 
presented on the figure attached.
Explanation:
For this case the figure attached shows the illustration for the problem
We have an inverse square law with distance for the force, so then the force of gravity between Earth and the spaceship is lower when the spaceship is far away from Earth.
Th formula is given by:
Where G is a constant 
represent the mass for the earth
represent the mass for the spaceship
represent the radius between the earth and the spaceship
For this reason when the distance between the Earth and the Spaceship increases the Force of gravity needs to decrease since are inversely proportional the force and the radius, and for the other case when the Earth and the spaceship are near then the radius decrease and the Force increase.
Based on this case we can create the following rank:
Where represent the force for each of the 5 cases presented on the figure attached.
Answer:
yes
Explanation:
objects with constant velocity also have zero net external force. this means the forces on the object are balanced. this mean they are in equilibrium
<h2>Question</h2>
why freezer is made in the upper part of refrigrator
<h2>✒ Answer</h2>
the cold air produced from it is denser than the warmer air in the bottom
<h3>Explaination</h3>
Freezer is normally provided at the top of the refrigerator, because density of the cold air is high compared to the hot air. In a refrigerator the air contacts with the cooling coil and gets cooling.Because of the high density the cold air gets down and the warm air/hot air moves upward and gets cooling from the cooling coil/evaporator coil. This process is repeated. If the Freezer is provided at the bottom place of the refrigerator, the cold air can't to move full area of the refrigerator. So the freezer is normally provided at the top at the refrigerator
