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?

Question

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?

anonymous · Answer

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!

anonymous · Answer

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

anonymous · Answer

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

anonymous · Answer

is the answer 75 m o-o

anonymous · Answer

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

anonymous · Answer

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

anonymous · Answer

great! good work! :)