Suppose that a Type II Cepheid has an apparent magnitude (m) of 12 and a pulsation period of 3 days. Use the chart at right along with the period to find the absolute magnitude (M). Then use the interactive tool on the distance modulus page to determine the distance to the Cepheid variable star. What is the distance?

the average speed is 24.57 km/hr

small = small current large mag large current

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.