Superman, with a mass of 150kg, goes into outer space to push a 125000kg alien spaceship out of stationary orbit. He uses his super strength and pushes the ship away ay at speed of 150m/s. What is the speed of Superman after his big push

125000 m/s

Explanation:

Applying the law of conservation of linear momentum, the sum of initial and final momentum must be equal. Momentum is given by p=mv where m is the mass of an object and v is the velocity.

Initial momentum

Both Superman and spaceship alien are initial at rest hence the velocity component is zero. This implies that the initial momentum is zero.

Final momentum

The final momentum must cancel out to be zero so as to obey the law of conservation of momentum. Given the masses and velocity then we deduce that

Mass of superman * velocity of superman + Mass of spaceship*velocity=0

150v + (125000*150) = 0

150v=-125000*150

v=-125000 m/s

Therefore, the speed of Superman is 125000 m/s in opposite direction to that of spaceship