A ball is projected horizontally from the top of a building. One second later, another ball is projected horiz

Question

A ball is projected horizontally from the top of a building. One second later, another ball is projected horizontally from the same point with the same velocity. At what point in the motion will the balls be closest to each other?
Will the first ball always be traveling faster than the second ball?
yes
no

What will be the time difference between them when the balls hit the ground?
no time difference
between one and ten seconds
one second
it depends on the height of the building

Can the horizontal projection velocity of the second ball be changed so that the balls arrive at the ground at the same time?
yes
no
Explain.

Answer 1

they would always be 1 second apart.. would they not, the would hit the ground 1 second apart, they would travel 1 second apart, and they would never be more or less then 1 second apart...


so yes one ball will always travel faster thn the other

on ball will hit the ground one second later then the other

and no it cant not unless, you speed up the second ball by one second.

Answer 2

Will the first ball always travelling faster the second ball?
Ans. Yes - the horizontal speed should be the same, but the vertical speed must be faster by 0.98 meter at any time.

time difference?
one second since they will follow the same path and started with the same velocity.

Can the horizontal projection velocity of the second ball be changed for the balls to arrive at the same time?
No. The horizontal velocity does not influence the time for the ball to hit the ground. It will always take the same time before the ball hits the ground, no matter what is the horizontal velocity,

Answer 3

The closest they will be to each other is when the first ball is just about to fall...4.9m apart. After 2 sec, they will be 14.7m apart and they will continue to get further and further apart until they hit the ground. Of course, they will be closer when they hit the ground, but the question states "at what point in the motion ".

The first ball will always be traveling faster than the second until it hits the ground.

They will hit the ground one second apart.

No. Regardless of the horizontal velocity, the verticle acceleration will always be the same (9.8 m/sec²) and the initial vertical velocity is zero in both cases.

The only way to make them arrive at the ground at the same time is to change the relative vertical velocity. The magnitude of the necessary difference will depend on the building height.