Abaseball is thrown vertically upwards and returns to the thrower three seconds later find speed at which the ball us thrown

14.7 m/s

Explanation:

Since the motion of the ball is a uniformly accelerated motion, we can find the initial speed by using the following suvat equation:

where

s is the vertical displacement

u is the initial velocity

t is the time

a is the acceleration

In this problem, we have:

s = 0 (because at the end of the motion, the ball returns to its original position)

u = ?

is the acceleration of gravity (negative because it is downward)

is the total time of flight

Solving for u, we find the initial velocity of the ball:

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.