A particle moves along a straight line with equation of motion s = t^{5} - 2 t^{4} Find the value of t (other than 0 ) at which the acceleration is equal to zero.

I took the second derivative got 20t^3-21t^2 factored but its still not the answer...

Question

A particle moves along a straight line with equation of motion s = t^{5} - 2 t^{4} Find the value of t (other than 0 ) at which the acceleration is equal to zero.

I took the second derivative got 20t^3-21t^2 factored but its still not the answer...

campbell_st · Answer

there is a problem with your derivative

 
$$ds/dt = 5t^4 - 8t^3$$

$$d^2s/dt^2 = 20t^3 - 24t^2$$

then

$$4t^2(5t - 6)$$
 t = 0 or 6/5 seconds

anonymous · Answer

I must be an idiot

anonymous · Answer

lol

anonymous · Answer

thank you its 1:24am here not a good time to be doing ds