Question

Two objects move with initial velocity -9.15 m/s, final velocity 18.3 m/s, and constant accelerations.The first object has displacement 19.5 m. What is its acceleration? The second object travels a total distance of 22.5 m. What is its acceleration?

Answer 1

`a_1=6.44m/s^2`,

`a_2=5.58m/s^2`.

Explanation:

The two laws of the accelerated motion are:

`s=s_0+v_0t+1/2at^2`

and

`v=v_0+at`.

But if you solve the system of the two equations, you can find a third law really useful in those cases in which you haven't the time, or you haven't to find it.

`v^2=v_0^2+2aDeltas` in which `Deltas` is the space run.

So:

`a=(v^2-v_0^2)/(2*Deltas)=(18.3^2-(-9.15)^2)/(2*19.5)=6.44m/s^2`,

`a=(v^2-v_0^2)/(2*Deltas)=(18.3^2-(-9.15)^2)/(2*22.5)=5.58m/s^2`.