Games in space: on earth, an astronaut throws a ball straight upward, and it stays in the air for a total of 3.0s before they catch it at the same height they released it. on the moon, acceleration due to gravity is ∼ 1/6 the value on earth. if the astronaut repeats this process on the moon, giving the ball the same initial speed, how much time would pass before they catch it

if an object is thrown upwards and then it will return back into our hand then we can say for the complete motion the displacement of the object must be zero

so here we will have

here we know that

now we will have this time t = 3 s on the surface of earth

again same experiment is performed on surface of moon with same initial speed

so the time on the surface of moon will be

so here we have

so it will take 18 s on moon

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.