In a cloud formation, water vapor condenses into water droplets which get bigger and bigger until it rains. This will cause the temperature of the air in the clouds to
A)
increase.
B)
decrease.
C)
stay constant.
D)
freeze.
Question 2
A 620-g object traveling at 2.1 m/s collides head-on with a 320-g object traveling in the opposite direction at 3.8 m/s. If the collision is perfectly elastic, what is the change in the kinetic energy of the 620-g object?
A)
It loses 0.23 J.
B)
It gains 0.69 J.
C)
It loses 0.47 J.
D)
It loses 1.4 J.
E)
The energy of the object is unchanged.