00:01
Hello in this question, the displacement from equilibrium of an object in harmonic motion on the end of a spring is given by y is equal to 1 divided by 3 cost 12 t minus 1 divided by 4 sine 12 t where y is measured in fit and t is the time in second.
00:25
So determine the position and velocity of the object when t is equal to pi divided by 8.
00:31
So the displacement is given by the formula.
00:34
Again i am writing f of t is equal to 1 divided by 3 cost 12 t minus 1 divided by 4 sine 12t.
00:48
So i have to find the position and velocity when t is equal to pi divided by n.
00:53
So the equation of displacement gives us the position.
00:58
So substituting t is equal to pi by 8.
01:01
8 it will come f of pi by 8 is equal to 1 divided by 3 cost 12 multiplied by pi divided by 8 minus 1 divided by 4 sine 12 multiply by pi divided by 8 so this is 1 divided by 3 it will be cos 0 cause it will be 90 so the value will be 0 multiply by 0 minus 1 divided by 4 value will come as minus 1 because 3 pi by 2 will be minus 1.
01:42
So this is 1 divided by 4.
01:45
Now this is the distance of the object at given t but it's from the equilibrium point not from the point t is equal to 0.
01:54
So next we have to find the velocity which is the first derivative of displacement...