## anonymous one year ago A 1000 kg aircraft going 25 m/s collides with a 1500 kg aircraft that is parked and they stick together after the collision and are going 10 m/s after the collision. If they skid for 5.5seconds before stopping, how far did they skid? Hint: Are the aircraft moving at a constant velocity after the collision or do they experience an acceleration?

1. anonymous

so, after the collision we have a big mass of metal with a speed of 10m/s, if it skids and then stops there should be an acceleration (in this case it should point against the velocity), so the starting velocity is $$v_0=10m/s$$ and, if we consider a constant acceleration we can use this equations for velocity and position: $$v=v_0+at$$ $$(1)$$ $$x=v_0t+\frac{1}{2}at^2$$ $$(2)$$ to find when and where the planes stop we must set $$v=0$$, and solve for $$t$$ and $$x$$ Give it a try!

2. anonymous

so if i'm solving for t and setting v to 0. T = -10/a

3. anonymous

yes... and you can plug that in eq(2) replacing $$t$$ by $$\frac{-10}{a}$$ and solving that for a :)

4. anonymous

is the answer 75 m o-o

5. anonymous

i get x=27.5m sorry i forgot the time was given in the problem! we need to use t=5.5 sec so a=-1.81m/s^2 please check your calculations

6. anonymous

Ok i got the same answer as you ! thankyou !! :D

7. anonymous

great! good work! :)