How much time does an object use to travel.

[Nerikk]

Homework Statement

How much time does the object use to travel 12m down a plane. The object has a constant acceleration of 1m/s² and the starting velocity is 5m/s.

Homework Equations

S=V(starting velocity)*t+1/2*a*t²

The Attempt at a Solution

Here I struggle with changing the formula. I could just leave both t's on the left side and then use square root. But I have a slight feeling that this is not right.

 

[Simon Bridge]

I could just leave both t's on the left side and then use square root. But I have a slight feeling that this is not right.

Very close - for that to work, the LHS needs to be a complete square.

Hint: quadratic equation

Aside:
I'm intrigued by the wording. Is time the sort of thing that gets used up by objects ... you know, like a car uses petrol?
Probably the question wants to know how much time is taken or occupied by an activity.

 

[Nerikk]

Yea, it's quite hard to word yourself correctly in another language. Especially in math. But I will check out quadratic equation! Thank you!

 

[Simon Bridge]

Oh it was a translation?! Well done - I couldn't tell. I wondered if maybe you just had a new-age physics teacher ;)
Since English is a second language ... I'll say a bit more.
The equation you are trying to solve can be put in form: $At^2+Bt+C=0$ - do so: A, B, and C, may be made of several variables.
You should recognize that as the equation for the roots of a parabola... you should know an equation to solve that. $$t\in \frac{-B\pm\sqrt{B^2-4AC}}{2A}$$

 

[Nerikk]

I think I need some more help on that one. First of all how do I achieve 0 on the right side of the equation. Second how do I determine the variables?

And thank you for all your help! It seems like I lack some fundamentals in physics, heh...