Answer:
Force to stretch the wire is 250 N
Explanation:
As we know that modulus of elasticity will remain the same for the wire if the applied stretch to the wire is within elastic limit
So we will have

now we have

so we can write it as



Answer: 80 s
Explanation:
Speed is expressed in v= d/t, derive the equation so we can have time.
First conert km into meters to cancel out both units and only seconds will remain.
1.2 km x 1000m/ 1km = 1200 m
t = 1200 m /15 m/s = 80 s