One billiard ball is shot east at 1.8 m/s . a second, identical billiard ball is shot west at 0.80 m/s . the balls have a glancing collision, not a head-on collision, deflecting the second ball by 90∘ and sending it north at 1.37 m/s .

Velocity of ball1 after the collision is 0.35 m/s at 53.87° due south of east.

Explanation:

By conservation of the linear momentum:

 Since both masses are the same, and expressing the equation for each axis x,y:

     eqX

                eqY

From eqX:  

From eqY:  

The module is:

The angle is:

  This is 53.87° due south of east

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.