Explanation:
When a bullet is fired from a rifle, the actual firing makes a distinctive sound, but people at a distance may hear a second because the bullet creates a shock wave , a little sonic boom( speed of this sonic boom is greater than the speed of sound). It is this sound only that is heard by the people at a distance from the gun.
Answer:
The initial speed of the ball is 3.93 m/s.
Explanation:
It is given that,
A ball is thrown horizontally from a height of 19 m, h = 19 m
Let u is the initial speed of the ball so, its final velocity, v = 5u
Using third equation of motion as :
u = 3.93 m/s
So, the initial speed of the ball is 3.93 m/s. Hence, this is the required solution.
Answer:
Gravity dams are so named because they are held to the ground by gravity – they weigh a lot, and are typically made from concrete or stone. Engineers must de-water the river where the dam is meant to be built. This is done by diverting the river through a tunnel that runs around the intended construction zone.
