Answer: C (impulse acting on the object)
The momentum is defined as it is the impulse acting on the force . Change in momentum is known as Impulse. Impulse is used to increase or decrease the momentum of object.
From Newtons II law
F = m. a
= m. v/t <em>since a = rate of change of velocity.</em>
<em> </em>F . t = m . v
F . t is known as impulse momentum
Our planet is closed system because there is a limit of how much matter could be exchanged.
The classical physics works on the Newton's laws of motion. It is applicable on heavenly bodies which are governed by the gravitational force. On the other hand, Quantum Physics is applicable for very low mass and sized bodies like electron, protons etc. The classical physics would accurately describe the motion of satellite moving with speed 7500 m/s using the following formula:

where G is the gravitational constant, M is the mass of the planet and v is the orbital speed. Then radius of the orbit can be described by this formula.
Answer:
The message (signal) coming from the earth was sent first.
Explanation:
The radio messages reach Mars simultaneously, because the distance from Earth to Mars and that of from Mars to Asteroid is same. But the passenger in the spaceship is moving relative to Mars towards Earth and hence, the message from Earth reaches first.
According to passenger frame, the message (signal) coming from the Earth was sent first compared to message coming from Asteroid.