IIT JEE , AIEEE Forum - Physics , Mechanics

waterdemon

Hiya Srujana met you after a long time.

I am also attaching a graph for your slope doubt.

Ok this Question can be done by Differentiation.I am giving you the rules of

I am solving the sum side by side as I am giving you the steps.

Differentiation to find Maximum and minimum value of a function :-

1)Suppose f(x) is the function given to you Then on differentiating it you can call the "Diffrentiated function" as f'(x)

So we get:

f(x) = 2t - 5t²

f'(x)= 2 - 10t

Now put the value of differentiated function = 0

f'(x)=0

2 - 10t = 0 we will get t = 1/5

2)Now differentiate the "already differentiated fuction"

f''(x) = double differentiated

f"(x)= -10

Since the value after double differentiation is < 0 we will get the minimum value of the function at t = 1/5 = 0.2sec

But as the f"'(x) = 0 we will get t = 0.2 sec as maximum.

If it would have been as derivative in terms of "t" then we would have put the value of t =1/5 in it and get its value.

And if the value is positive .minima at t =1/5

and if negative maxima at t = 1/5

the maximum height reached is

h=2t - 5t² = 2(1/5) - 5(1/25) = 2/5 - 1/5 = (1/5)

Hence the maximum height reached will be 0.2m

Hope you understood my explanation

Cheers !!!!!!!!!!!!!!!!!!!!!