In an amusement park ride, children are spun in a large cylindrical chamber so that they are pressed against the wall. The floor then drops out, and hopefully the children remain attached to the wall. If the coefficient of friction between a boy and the wall is 0.17, at what angular velocity must the boy be spun in a cylinder of radius 4.23 m so that he doesn't slide down the wall?

d is the correct answer

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.