Owarm up some milk for a baby, a mother pours milk into a thin-walled glass whose diameter is 6 cm. the height of the milk in the glass is 7 cm. she then places the glass into a large pan filled with hot water at 60°c. the milk is stirred constantly, so that its temperature is uniform at all times. if the heat transfer coefficient between the water and the glass is 120 w/m2·°c, determine how long it will take for the milk to warm up from 3°c to 38°c. take the properties of the milk to be the same as those of water.

heats surface water up

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.