Answer:b
Explanation:
Given
mass of first cart 
mass of second cart 
velocity of first cart 
conserving momentum



Initial kinetic Energy 


Final Kinetic Energy


Ratio of initial Kinetic Energy to the Final Kinetic Energy

Answer:
Since the wire is not splitting at any point in the circuit,
the resistors are in series
Hence, Equivalent resistance = 10 + 20 + 30
Equivalent Resistance = 60 Ω
Answer:
C. The car from driving off the road on a curve
Explanation:
A centripetal force actually causes circular motion. This occurs when an object moves in a circular path or a circle,a force will definitely act on it.
For instance, a car travelling in a circular path must definitely experience this force acting on it, even when the car moves at a constant speed. If it does not exist the object will definitely spin off in a direction tangential to the circular path or curve.
He preformed the first ever successful open heart surgery
Kinetic energy is energy that a body possesses by virtue of being in motion, there for if an object is moving, it has kinetic energy.
Example; A roller coaster sitting on top of hill has potential energy. When it starts to move and is going down the hill, it has kinetic energy. :)