The talk test can be used to measure the
A knowledge of an activity
B. intensity of an activity
C. length of an activity
D. cost of an activity
Please select the best answer from the choices provided.

The talk test can be used to measure the intensity of an activity

Option: B

Explanation:

The talk test is usually used to measure the intensity of a particular activity when a person talks during that activity. This is mostly used in cardiovascular patients to measure the intensity of the exercise.

For example, when a person can talk during exercising, it means that he is able to use the oxygen to create energy for the muscles. i.e he will be in aerobic state. Incase, he is not able to talk any more during his exercise, it means that the breathing rate has reached a particular ventilatory  threshold.

So now the body is creating energy from the stored system such as muscle glucose and creatine. Thus this talk test helps to determine in which way your body creates energy, aerobic or non aerobic.

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.