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.
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Answer: 0.258 N
Explanation:
As the density of the object is much less than the density of water, it’s clear that the buoyant force, is greater than the weight of the object, which means that in normal conditions, it would float in water.
So, in order to get the ball submerged in water, we need to add a downward force, that add to the weight, in order to compensate the buoyant force, as follows:
F = Fb – Fg
Fb= δH20* 4/3*π*(d/2)³ * g
Fg = δb* 4/3*π*(d/2)³ *g
F= (δH20- δb) * 4/3*π*(d/2)³*g
Replacing by the values of the densities, and the ball diameter, we finally get:
F= 0.258 N
Answer: 500 s
Explanation:
Speed
is defined as a relation between the distance
and time
:

Where:
is the speed of light in vacuum
is the distance between the Earth and Sun
is the time it takes to the light to travel the distance
Isolating
:


Finally:

Kinetic energy is the energy the makes an object move.