00:01
We would first like to find the acceleration, so we can use newton's first law of motion, v is equal to u plus a times t.
00:08
So acceleration is v minus u divided by t.
00:12
We just need to solve for t first.
00:14
Now we can use the second law of motion ut plus one -half a -t squared.
00:19
Let's substitute in, and we'll have u -t plus one -half t times v minus u.
00:25
We're just substituting our a here.
00:28
And now we can substitute our values.
00:30
Is equal to 20 meters per second times t plus 1 half t times 0 .5 meters per second minus 20 meters per second.
00:38
We get a t equal to 100 divided by 10 .25, which is 9 .75 seconds.
00:45
So finally, our acceleration is 0 .5 minus 20 divided by 9 .75, which gives us negative 2 meters per second squared...