A particle moves in a straight line through a fixed point O with a velocity (4-t)m/s find an expression for its displacement S from this point given that S=S when t=0

S = 4t - (1/2)t^2 + c

"given that S=S when t=0" ?????
I will assume you meant: given that S=0 when t=0

0 = 0 - 0 + c ---> c = 0

S = 4t - (1/2)t^2

To find an expression for the particle's displacement from the fixed point O, we need to integrate its velocity function. The velocity function is given as (4-t) m/s.

Let's integrate the velocity function to get the expression for displacement S:

∫(4-t) dt

To integrate the function, we can use the power rule of integration:

∫(4-t) dt = ∫4 dt - ∫t dt

The integral of a constant is the constant times the variable:

∫4 dt = 4t

The integral of t with respect to t is (t^2)/2:

∫t dt = (t^2)/2

Combining the integrals, we have:

∫(4-t) dt = 4t - (t^2)/2

Now, to find the value of displacement S, we replace t in the expression for displacement with the given value when t=0:

S = 4t - (t^2)/2
S = 4(0) - (0^2)/2
S = 0

Therefore, when t=0, the particle's displacement from the fixed point O, S, is 0.

The final expression for the displacement S from the fixed point O is:

S = 4t - (t^2)/2