00:01
Hi, so on this question, you have the position of a particle given by r is equal to 4 .3 t minus 6 .74 t squared i plus 3 .5 t cubed j.
00:24
Now to find the velocity, we're going to differentiate this.
00:29
And then to find the acceleration, we're going to differentiate the velocity.
00:31
So our v for the velocity equal to the r the t.
00:36
So i depreciating with respect to time.
00:40
And so well when to differentiate, is differentiate this separately.
00:43
Differentiate the separately.
00:44
Just forget about the i's and js for now.
00:47
Just differentiate it with the i's demarcating the different directions.
00:53
So we have 4 .3 minus differentiating this is 2 times 6 .7.
01:04
And this is i now with differentiate j separately 3 times 3 .5 t squared for j now with differentiate this again to find a so this becomes error so we just have 2 minus 2 times 6 .74 i plus this comes 3 times 2 times 3 .7 4 i plus this comes 2 times 3 which is 6 times 3 .5 t j so next at t is equal to 1 .5 we're going to have we're simply substitute 1 .45 rather 1 .45 seconds into the equation so a 1 .45 be equal to minus 2 6...