Constant Acceleration - Kinematics Problem Help

[dd12]

Homework Statement

A train at constant acceleration is traveling in a straight line. It passes two points at a velocity of 50km/h and 80km/h respectively. What is the exact velocity of the train when it is halfway between these two points?

Let v be the exact velocity of the train when it is halfway between these two points

(Must be solved using two simultaneous equations)

Thanks! :)

Homework Equations

The Attempt at a Solution

 

[Kurdt]

So what have you tried?

 

[dd12]

Using formula V^2=(V(0))^2+2*a*s
where a is acceleration, s is displacement, v is velocity, V(0) is initial velocity:

80^2=50^2+2as (1)
M^2=50^2+(1/2)*2*as (2)

where M is the velocity at halfway

Solved them simultaneously and got M=5*sqrroot(178)

 

[zakaqel]

You got the right answer...