A science teacher ran a marathon. After the race she showed her students the silver blanket she was given to keep her warm. A group of students investigated how the colour of the blanket affected how much infrared radiation is absorbed

In summary the blanket that is metallic reflects electromagnetic waves

Explanation:

The teacher running the marathon generates a quantity of heat that the body must release to keep its temperature constant, one of the ways to release this energy in the form of electromagnetic radiation in the infrared range.

The matte with is silver should be metallic, so it reflects light at all wavelengths, so that the infrared light returns to the body and decreases the radiation radiation emitted, thus keeping it warmer.

In summary the blanket that is metallic reflects electromagnetic waves

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.

answer: 2×10^-2kg

explanation: density= mass per volume

vol=mass/density

converting to s.i units we have;

3÷1000kg = 0.003

1.5÷100m = 0.15

0.003/0.15 = 0.02kg