The answer is D. Mass, brightness and size are used to measure the physical properties of the stars. One is the brightness it is a combination of the intrinsic brightness of a star. Second is the size is calculated using the Stephan's Law. And the third is the mass, astronomers use the Stellar mass to describe the mass of the stars.
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Answer:
You can determine which charge has the solid by rubbing plastic and fur, and bringing near the plastic and the solid to determine if they are repeled or attracted. If they are repeled, the solid is charged negatively and if they are attracted, the solid is charged positively.
Explanation:
In order to determine the charge of the solid (negative or positive) using a piece of plastic and fur, you have to rubb the plastic with the fur (this is charging by friction)
Negative charges are transferred from the fur to the piece of plastic, therefore the plastic is charged negatively.
Then, you have to bring near the solid and the plastic. If them are repeled, it means that the solid is charged negatively (Because similar charges are repeled)
If them are attracted, it means that the solid is charged positively (Because opposite charges are attracted)
Answer:
F = K Q1 * Q2 / R^2 force between 2 charged particles
F2 / F1 = R1^2 / R2^2 = (R1 / R2)^2 = (R1 / R1 /2)^2 = 2^2 = 4
d) the force would be increased by a factor of 4
Solution :
Let the positive 
is along the East and the positive 
direction is along the north.
Given :
Mass of the Tesla car, 
= 
Mass of the Ford car, 
Now let the initial velocity of Tesla car in the south direction be = 
The initial momentum of Tesla car, 
Let the initial velocity of Ford car in the east direction be = 
So the initial momentum of the Ford car is 
Therefore, the initial velocity of both the cars is 
Now the final velocity of both the cars is 
So the vector form is :
Therefore the momentum after the accident is
According to the law of conservation of momentum, we know
From, 
We get, 
Therefore the speed of Tesla car before collision = 25.4 m/s
The speed of ford car before collision = 24.4 m/s
