The answer is D.
Mechanical waves need a medium to travel, for example, sound is a mechanical wave. You are able to hear other people because the sound wave is travelling trough a fluid -air-. If you were to be in space -vacuum- you would not be able to hear anything.
The most well known example of an electromagnetic wave is light. As you may have noticed, we're able to get the light from the Sun to Earth; clearly light -electromagnetic wave- is able to travel in vacuum/space (i.e., without a medium).
Answer:
★The second law of refraction
The ratio of sine of angle of incidence to the sine of angle of refraction is a constant for a light of given colour and for a given pair of media. This law is also called Snell's law of refraction. If 'i' is the angle of incidence and 'r' is the angle of refraction then, Sin i/Sin r = constant
This constant value is called the refractive index of the second medium with respect to the first.
initially coin is at rest and then it drop for total time t = 1.5 s
so here the speed of the coin at which it will hit the floor is to be find

here we know that

a = 9.8 m/s^2
t = 1.5 s
now from above equation


so it will hit the floor with speed 14.7 m/s
it's how much it weighs and how much force is pushing on it like a egg if i drop it the weigh can cause it to break and how much force the gravity is pushing on it.
Answer:
The final velocity of the car is 26.65 m/s.
Explanation:
Given;
acceleration of the racecar, a = 6.5 m/s²
initial velocity of the car, u = 0
time of motion, t = 4.1 s
The final velocity of the car is given by;
v = u + at
where;
v is the final velocity of the car
suvstitute the givens
v = 0 + (6.5)(4.1)
v = 26.65 m/s.
Therefore, the final velocity of the car is 26.65 m/s.