Momentum is conserved, so the sum of the separate momenta of the car and wagon is equal to the momentum of the combined system:
(1250 kg) ((36.2 <em>i</em> + 12.7 <em>j </em>) m/s) + (448 kg) ((13.8 <em>i</em> + 10.2 <em>j</em> ) m/s) = ((1250 + 448) kg) <em>v</em>
where <em>v</em> is the velocity of the system. Solve for <em>v</em> :
<em>v</em> = ((1250 kg) ((36.2 <em>i</em> + 12.7 <em>j </em>) m/s) + (448 kg) ((13.8 <em>i</em> + 10.2 <em>j</em> ) m/s)) / (1698 kg)
<em>v</em> ≈ (30.3 <em>i</em> + 12.0 <em>j</em> ) m/s

Displacement measures how far it is from the starting point and the final location, which in this case is the distance between Honolulu and Los Angeles. The difference between distance and displacement is that distance measures how far the object actually travels. For example, the airplane may not fly in a straight line and it may have detours, making the distance much greater than the displacement.
On the other hand, the plane could fly at different speeds at different periods of time. It will be so much more complicated if we have to calculate it. That's why this question only asks you to calculate the average velocity of the plane, ie. 
So, we have
the required average velocity = 
= 511.6 miles/hour
Hope this helps!
Answer:
Explanation:
The complete question is here.
A spring is compressed between two objects with unequal masses, m and M, held together. The objects are initially at rest on a horizontal friction less surface. When released, which of the following is true?
a) Kinetic energy is same as before being released
b) The total final kinetic energy is zero.
c) The two objects have equal kinetic energy.
d) The speed of one object is equal to the speed of other.
e) The total final momentum of two objects is zero.
So option e) the total final momentum of two objects is zero.