00:01
Hi, in this question given that the height of the object projected upwards after t seconds is given by s of t equals minus 16 t squared plus 128 t.
00:14
We need to find the number of seconds it will take to reach its maximum height.
00:20
So here, this is like quadratic equation so that we know that the formula to find the maximum height.
00:32
For quadratic equation is c equals minus b by 2a.
00:39
Here, a is less than 0.
00:44
On here, general quadratic equation is a x square plus bx plus c equals 0.
00:53
On equating this two, we can conclude that a equals minus 16, b equals 128 and c equals 0.
01:03
Therefore, t equals minus 128 divided by 2 into minus 16.
01:12
On further simplification, we get minus 128 divided by minus 32.
01:19
On canceling, we get 4.
01:21
Hence, we conclude that it will take 4 seconds to reach it maximum height...