Football player A has a mass of 210 pounds and is running at a rate of 5.0mi/hr. He collides with player B. Player B has a mass of 190 pounds and is running in the same direction at 3.0 mi/hr. Which of the following statements is true? The momentum before the collision is equal to the momentum after the collision.
The momentum before the collision is greater than the momentum after the collision.
The momentum before the collision is less than the momentum after the collision.

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

Decreased sensitivity to an unchanging stimulus is known as

Positive ions differ from neutral atoms in that