I believe the answer is the first one.
Average velocity = Total Displacement / Total time taken
Total displacement is the distance from starting to end point.
35km west then 90km north. When you will draw this and connect starting to end point. You will get a right angled triangle.
So displacement =

= 96.56 km
So, Total displacement = 96.56 km
So, Average Velocity = 96.56 / 2 = 48.28 km/hr
Length of the copper rod = 2.5 meters
Speed at which sound travels through copper = 3560 meter per second
Let us assume the time taken
by sound to cover the given distance = x seconds
We already know that
Speed = Distance/ Time
Then
Time = Distance/ Speed
x = 2.5/3560 seconds
= 0.0007 seconds.
This can ve done by hitting one end of the rod and then receiving the sound at the other end and using the stop clock to measure the time taken.
Explanation:
If box weight 25N on ground
MA=F
M(10)=25
M=2.5Kg