00:01
In this problem, we are given that there is a ball.
00:05
And this ball is kicked such that the initial velocity in the horizontal direction, that is 17 meter per second, and in the vertical direction, this is 11 meter per second.
00:19
And we are required to determine first the speed with which this ball will hit the ground.
00:25
So we see that in the horizontal direction, there is no acceleration.
00:30
So although this ball is going to follow the curved path, but still the velocity in the horizontal direction that would remain same at every point.
00:40
So that will be 17 meter per second at the time when it hits the ground and the vertical component descends from 11 to 0 to the top and again it will increase to 11 meter per second because of gravity.
00:57
So we see that the speed with which it hits the ground that would be root of 11 square plus 17 square and this turns out to be 20 .25 meter per second and next we are required to determine the time for which this ball remained in air so we're going to consider the motion in the vertical direction and let's use this equation so the time which this ball takes to reach the top let's say it's t and the the final velocity at the top would be zero.
01:33
So we put the values in this equation and we get zero equal to 11 minus 9 .8 times t because here the acceleration is due to the gravity and that's in the downward direction...