Answer:
Explanation:
For a linear elastic material Young's modulus is a constant that is given by:
Here, F is the force exerted on an object under tensio, A is the area of the cross-section perpendicular to the applied force, 
is the amount by which the length of the object changes and 
is the original length of the object. In this case the force is the weight of the mass:
Replacing the given values in Young's modulus formula:
Yo sup??
since the collision is elastic therefore we can say that the two balls will then move in opposite direction.
If ball 1 was moving from east to west then after collision it will move from west to east
and if ball 2 was moving from west to east then it will start moving from east to west.
Hope this helps.
When looking for distance you multiply speed by time
So 15 x 2 = 30
30 is the distance between his house and school
