Why are astronauts weightless in the space station? you may find it to watch the video "newton's laws of motion." why are astronauts weightless in the space station? you may find it to watch the video "newton's laws of motion."
a) because the space station is moving at constant velocity.
b) because the space station is constantly in free-fall around the earth.
c) because there is no gravity in space.
d) because the space station is traveling so fast.

B) Because the Space Station is constantly in free-fall around the Earth.

Explanation:

Anything that is falling experiences an upward force on them. For example when a person is going down in a lift they will experience something that is pushing them upwards. This happens due to the fact that the total acceleration the body is feeling is less than the acceleration due to graviity.

The force on a body which is falling is

Where,

m = Mass of object

g = acceleration due to gravity

a = acceleration the object is experiencing.

a = g. So, the force becomes zero and the object experiences weightlessness.

Hence, the astronauts in the space station experience weightlessness due to fact that the Space Station is constantly in free-fall around the Earth.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s