Which of the following is NOT a reason density decreases as altitude increases? A. There is less air pushing down from above so molecules can spread out
B. Gravity is weaker the farther you get from Earth's core
C. Living things have breathed in much of the air molecules so there are less in the atmosphere

What challenges did you encounter during the circuit training program?

The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.

Suppose a soccer ball is kicked from the ground at an angle 20.0º above the horizontal at 8.00 m/s. the y-velocity is determined to be 2.74 m/s. how long will the ball be in the air? assume the ball lands at the same height at which it was kicked.