Answer:
2.4 mm
Explanation:
Given that:
Initial Original length of the wire L = 3 mm
The stretch of the first wire ΔL= 1. 2 mm
The length of the second wire L'' = 6 mm
The stretch of the second wire ΔL'' = ???
Considering the Tension of the system; the Young modulus and the cross sectional remains constant ; as such:





Thus, the same material under the same tension stretches 2.4 mm
B because the skater is constantly moving in the same speed to go in a circle .
Acceleration = (final velocity - initial velocity) / time
= (35-65)/10
= -3 m/s2
To solve this problem we will apply the principle of conservation of energy and the definition of kinematic energy as half the product between mass and squared velocity. So,


Here,
m = Mass
V = Velocity
Replacing,


Therefore the final kinetic energy of the two car system is 72.6kJ