The velocity acquired by a body moving with uniform acceleration is 12 m/s in 2 s and 18 m/s in 4 s. find the initial velocity of the body.

6 m/s

Explanation:

At constant acceleration, the final velocity is equal to the initial velocity plus the product of time and acceleration:

v = at + v₀

We know that at t=2, v=12.  And at t=4, v=18.

12 = 2a + v₀

18 = 4a + v₀

We can solve the system of equations for v₀.  If we double the first equation:

24 = 4a + 2v₀

And subtract the second:

24-18 = 4a-4a + 2v₀ - v₀

6 = v₀

The initial velocity is 6 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.

a is the best answer your welcome