Whenever an object is in projectile motion, that is, it has 2-dimensional motion in the x and y axis, the resultant force on the object is in the y-direction.
This is because once the object has been projected, or the ball has been kicked in this case, there is no longer a force being applied on it in the x-direction. The air resistance is also neglected so the ball's final velocity in the x-direction is equal to its initial velocity in the x-direction.
However, the force of gravity cannot be neglected and causes the ball to come downwards. Therefore, after the ball has been projected, the net force on the ball is downwards, due to gravity.
<span>We know that the momentum keeps constant in a inelastic collisions, so the product of mass and speed do not change:
m1 * v1 + m2 * v2 = m * v
1 * 1 + 5 * 0 = (1 + 5) * v
1 = 6 * v
v = 1/6 m/s
So the final speed of the 6 kg chunk will travel at 0.167 m/s</span>
When you talk about rate, you will expect that it will be in terms of a time unit. It measures how fast it is going. So, you would expect that the denominator is in time units. For the movement, you can measure this with either distance or velocity.
So, for the first variety, you would need distance and time to measure the rate of how far you go at a certain time. It is also called as velocity. For the second variety, you would need velocity and time to measure the rate of how fast you are going at a certain interval. It is also called as acceleration.
