displacement & time maths problem?

Question

The displacement, s (m), of an object from a fixed point O can be described as a function of time, t (s), as

s=6t^4 - 2t^3 + 3t +2

Determine the displacement, velocity and acceleration of the object at t=5s. Calculate the times when the acceleration, a (m/s^2), is zero.

Answers below:

@t=5s

displacement= 3517m
Velocity= 2853 m/s
Acceleration = 1740 m/s^2

Then it says..
Acceleration = 0 m/s^2
@t=0s or t=0.17s

can anyone help explain and show the work? 

best answer awarded.

vadaptre · Accepted Answer

OK..S=6t^4-2t^3+3t+2=displ funct.sub t=5..>S=3517m
v=S'=24t^3-6t^2+3=vel func..sub t=5 agn..> v=2853
a=S''=72t^2-12t= accel func..sub t=5..........> a=1740
a=0 when 72t^2-12t=0..or 6t^2-t=0..or t=1/6=0.16666..etc

displacement & time maths problem?

1 Answer