Solving SUVAT: Finding T from 2.5m/s to 7.5m/s over 45m

[benbrooks]

Homework Statement

A mass accelerates from 2.5ms^(-1) to 7.5ms^(-1) over a distance of 45m. Find the acceleration and the time it takes to do this.

Homework Equations

I know I need to use s=0.5(u+v)t

But I have no idea how to rearrange it to find t, I am useless at rearranging equations.

The Attempt at a Solution

I got t=0.5(u+v)-s

I know I did it wrong because I have the answer to the questions here, But It's not really what I'm looking for.

I need to know how to do it.

Any help would be appreciated.

Cheers,
Ben

 

[gabbagabbahey]

if I gave you the equation $y=Ax$...could you solve it for $x$?

 

[Chi Meson]

The "0.5(u+v)" part of the equation is the "average speed." Quite literally it is one half of the sum of initial and final velocities. If it is written as (u+v)/2 it makes more sense.

But I am guessing (based on the way you wrote the unit for velocity) that your textbook, or teacher, likes to put everything "above the line."

Anyway, to solve for t, multiply both sides of the equation by 2, then divide both sides by (u+v).

Warning: you better get better than "useless" at algebraic manipulation really quickly, otherwise Physics will get impossible for you. This is one of the main features of problem solving. Get tutorial help ASAP

 

[benbrooks]

The "0.5(u+v)" part of the equation is the "average speed." Quite literally it is one half of the sum of initial and final velocities. If it is written as (u+v)/2 it makes more sense.

Something in your explanation made everything click into place. I guess the late nights aren't helping at the moment. Thanks very much and I'm looking into getting extra tuition.

Thanks once again,
Ben