Gravity obeys the inverse square law. At 6400 km above the center of the Earth (Earth's surface) you weigh x. Twice that reduces your weight to 1/4th. Four times that height reduces your weight to 1/16th. 4 times 6400 km is 25,600 km. But that is above the center of the earth, and the question requests the height above the surface, so we deduct 6400 km to arrive at our final answer: 19,200 km.
Incidentally, it doesn't exactly work the opposite way. At the center of the Earth the mass would be equally distributed around you, and you would therefore be weightless.
To respond to the question, we need the data provided with the question.
Hey can u give a little more detail?
Answer:
P = (2 + 3) * V where V is their initial speed (total momentum)
P = 2 * 10 + 3 * Vx where Vx here would be V3
If the initial momentum is not known how can one determine the final velocity of the 3 kg obj.
Also work depends on the sum of the velocities
W (initial) = 1/2 (2 + 3) V^2 the initial kinetic energy
W (final) = 1/2 * 2 * V2^2 + 1/2 * 3 * V3^2
It appears that more information is required for this problem