D) The marble’s horizontal velocity changes, but its vertical velocity does not.
Projectile motion is a kind of change undergone by an object or particle that is submitted near the Earth's cover and runs along a rounded path under the act of gravity only. This curved way was given by Galileo to be a parabola. The regular segment of the speed of the object continues constantly during the motion. The vertical segment of the changes linearly, because the acceleration due to pressure is uniform. The accelerations in the x and y tracks can be combined to determine for the segments of velocity at any time t.
In this problem, we are given that the mass of the man is 250kg and the net force on the man is 625N. To find the acceleration, we have to use Newton's second law of motion. Newton's second law of motion states that ,where is the net force on the object, is the mass of the object and is the acceleration of the object. In simple terms, the law states that the force on an object is directly proportional to the mass.
To figure out the acceleration of a man sliding down the hill, we have to solve for the acceleration in Newton's second law. This operation is done as shown below,