Answer:


Explanation:
m = Mass of each the cars = 
= Initial velocity of first car = 3.46 m/s
= Initial velocity of the other two cars = 1.4 m/s
v = Velocity of combined mass
As the momentum is conserved in the system we have

Speed of the three coupled cars after the collision is
.
As energy in the system is conserved we have

The kinetic energy lost during the collision is
.
Answer:
No,
Explanation:
An electromagnetic wave is made of vibrating electric and magnetic fields that continually induce each other; matter is not needed for this to occur.
Answer:
Twice
Explanation:
From the formula for velocity in a circle
V= 2πr/T
Where V is velocity
r is raduis
T is period
We see that as r increases V increases so if r is doubled V becomes doubled