The answer is B because, in reality, the force of gravity on astronauts, just depends on their masses which do not change, though the spacecraft is subjected to an acceleration upward.
Due to the acceleration of the spacecraft, is exerted on the astronaut additional acceleration equal to 0.2 g. In this case the astronaut has a greater apparent weight, which is equal to 1.2 mg although the gravitational force of the earth on the mass of the astronaut is still mg. Let's see this with the second law of Newton.
By Newton's second law we have:
∑ F = ma
The forces acting on an astronaut are the force of gravity or the weight, directed downward, and the force of the rocket boosters Fr, directed upwards. Then we can write:
Fr – mg = ma
Where (a = 0.2g) is the acceleration of the spacecraft ; so we have:
Fr = ma + mg → Fr = m(a + g) → Fr = m(0.2g + g) → Fr = 1.2mg
Fr is the apparent gravitational force (apparent weight) experienced by astronauts
An astronaut of mass m in a spacecraft experiences a gravitational force F=mg when stationary on the launchpad.
What is the gravitational force on the astronaut when the spacecraft is launched vertically upwards with an acceleration of 0.2g?
A 1.2mg
B mg
C 0.8mg
D 0
Ans= B
Someone explain pleaseeee!
And working too!
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3 answers
Gravitational force does not alter when the spacecraft is launched. So it is B
The gravitational force is m g
However the spring scale that astronaut is standing on would show 1.2 m g because the total force up = m g + ma
because
force up from scale - m g down = m a
However the spring scale that astronaut is standing on would show 1.2 m g because the total force up = m g + ma
because
force up from scale - m g down = m a
2 answers