00:01
In this problem, there is a ball which is thrown up with an initial velocity of 15 meters per second.
00:09
So of course this is thrown up against the effect of gravity.
00:13
So the acceleration here will be negative of 9 .8 meters per second square.
00:21
And here we are considering the point about which it is projected as the origin point.
00:28
And we need to figure out the displacement that is covered by this ball thrown up in the time.
00:36
0 .5 seconds.
00:39
Displacement in the time that is 1 second and displacement in the time that is 1 .5 seconds.
00:51
And finally, the displacement when t is equal to 2 seconds.
00:56
So here first let's just figure out the time it takes to reach the top because then we will be sure that this displacement is just going to be in the upward direction or whether there will be any return.
01:10
So at the topmost point, the velocity becomes zero.
01:13
So we use the sivots equation, v equals u plus 80.
01:17
So 0 equals 15 minus 9 .8.
01:21
So from here if we divide 15 by 9 .8, we get the time here as 1.
01:28
1 .53 seconds.
01:30
So that means for the fourth case we need to be quite careful because here the displacement will be somewhat different but nevertheless we're going to use the direct equation of finding the displacement s equals u t plus half a t square.
01:48
So in the first case the displacement we'll just substitute t as 0 .5 and the acceleration as 9 .8 so this simply to 15 t plus half into minus 9 .8 t square.
02:07
So that will be 15 t minus 4 .9 t square.
02:13
So let's just substitute the value of t as 0 .5 and that gives us the value of of displacement as 15 times 0 .5 minus 4 .9 times 0 .5 square...