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A particle is moving so that at time t, the distance is given by the function:

s(t) = -1/3(t)^3 - 5/2(t)^2 + 6(t)

At what time t greater than zero is the speed equal to zero

2006-10-02 14:13:58 · 3 answers · asked by Anonymous in Science & Mathematics Mathematics

3 answers

The speed is given by

s'(t) = -t^2 - 5t + 6.

Factor this. First, factor out a -:

s'(t) = -(t^2 + 5t - 6).

Then factor the rest:

s'(t) = -(t + 6)(t - 1).

Then s'(t) = 0 when t=-6 or t=1. Therefore your answer is t=1.

2006-10-02 14:16:59 · answer #1 · answered by James L 5 · 1 0

let s = -1/3(t)^3 - 5/2(t)^2 + 6(t)

If you differentiate the above equation, you will get the speed, hence ;

s'(t) = -t^2 - 5t + 6

When speed or s'(t) = 0,
hence

0 = -t^2 - 5t + 6
solve for t with (-b (+ or -) root (b^2 - 4ac)) / 2a

you will get t is either 1 or -6

t is time and wouldn't be -ve, hence the answer shall be 1 second

2006-10-02 21:23:39 · answer #2 · answered by Mr. Logic 3 · 0 0

Man, I thought it said cat question. My eyes are getting bad. Who's going to want to do your math homework for you?

2006-10-02 21:21:39 · answer #3 · answered by Jenny 4 · 0 0

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