You throw a tennis ball straight upward. the initial speed is about 12 m/s. part a how long will it take for the ball to reach its maximum height? express your answer to three significant figures and include the appropriate units.

1.2 s

It is given that a ball is thrown vertically upwards with initial velocity, u= 12 m/s.

At the maximum height, instantaneous velocity would be, v= 0 m/s

the ball would decelerate due to gravity,

using equation of motion,

Hence, the time taken by ball to reach its maximum height is 1.2 s when thrown vertically upward with initial velocity of 12 m/s.

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.

powerful computers now, not then