How do you solve for t in the equation d=v1(t) + .5at2?

[homevolend]

Homework Statement

I use this formula for a question I am doing, I know formula is correct one to use


d=v₁(t) + .5at²

The Attempt at a Solution

I do

4=0 t + .5 x 0.8 x t²

these are correct numbers in my equation I use.

I try to finding t, but I do not know since there is a t² at the end of the equation.

 

[fss]

It's basic algebra. Since the t term goes away due to being multiplied by 0, you have

4 = .4 t²

You should be able to solve that with little difficulty.

 

[homevolend]

Ok I have found out

t² = 10

But is that it or do I need to just make t alone without it squared?

 

[fss]

t² has units of seconds², which usually isn't very useful ;-)

 

[donutz610]

You can find t very simply:
With your first equation you can use the quadratic formula to solve for t.
You could also simplify it down giving you .4t to the second equals 4 in which you divide by .4 and take the square root of 4/.4.

 

[Paulie323]

This may seem confusing but it is only a simple algebraic equation.your first step should be isolating your variable t (in your case). Doing this will leave you with an equation something like this: (4/0.4)=t^2. This was done by dividing over the product of 0.8 and 0.5 (0.4) and the t is canceled out of the first part of the equation because it is multiplied by zero.

Now that all of that is sorted out comes time to solve for t! after finding the quotient of (4/.4) to solve for t you must take the square root of both sides of the equation this will put t in the first power and once you take the square root of your newly found quotient you will have successfully solved for t.