Answer:
B. When the racket hits the tennis ball with a force, the tennis ball applies an equal but opposite force to the racket.
Explanation:
According to the Newton's third law of motion every action has equal and opposite reaction. So, when the force is applied by the racket on the ball then the ball also applies an equal intensity of force in the opposite direction on the racket. It is just that the the force on the racket is absorbed by the player holding it.
Answer:
Explanation:
Given
Weight of person 
At highest point Magnitude of the normal force 
net force at highest point
where 
centripetal force
Normal Force
Negative sign shows force is in upward direction
At bottom point centripetal force is towards the bottom
Answer:
The speed decreases.
Explanation:
This can be explained using the conservation of linear momentum.
Since there is no friction, the initial moment of the train must be equal to its linear moment after it is filled with water.
the initial linear momentum is
where 
is the initial mass of the train, and 
the initial speed of the train.
And linear momentum after the water filled the train car is
where 
is mass of the train after the rain, and 
the speed of the train after the rain
<u>the equality must be fulfilled:</u>
We know that if water is added to the train, that is the mass after the water is added, is greater than which is the mass of the train without the water.
Therefore, in order for the conservation of the linear momentum to be fulfilled:
the speed after the water is added ( ) must be smaller than the initial train speed ( ) . So the speed of the car decreases.
The idea behind capitalism is that the free market of products and ideas is owned and driven by private citizens. A capitalist society is a social order in which private property rights and the free market serve as the basis of trade, distribution of goods, and development.
In short, the key value added of CDR data over census or survey approaches is the potential to access current and comprehensive evidence on population size, density, and dynamics, information that is fundamentally necessary for managing any humanitarian emergency or disease-related disaster but which is often
