Answers:
a) 5400000 J
b) 45.92 m
Explanation:
a) The kinetic energy 
of an object is given by:
Where:
is the mass of the train
is the speed of the train
Solving the equation:
This is the train's kinetic energy at its top speed
b) Now, according to the Conservation of Energy Law, the total initial energy is equal to the total final energy:
Where:
is the train's initial kinetic energy
is the train's initial potential energy
is the train's final kinetic energy
is the train's final potential energy, where 
is the acceleration due gravity and 
is the height.
Rewriting the equation with the given values:
Finding :
Answer:
Newton's Third Law of Motion
Explanation:
Newton's Third Law of Motion which states that, for every action there is an equal but opposite reaction.
This ultimately implies that, in every interaction, there is a pair of forces acting on the two interacting objects.
In this scenario, a ball bounced by a basketball player on the floor bounces back up at her.
According to Newton's Third Law of Motion, the statement above simply means that in every interaction, there is a pair of forces acting on the two interacting objects i.e the ball and floor. The size of the force on the ball equals the size of the force on the floor. These two forces are called action and reaction forces and are the subject of Newton's third law of motion.
Hence, the ball bounced by the basketball player on the floor would bounce back in equal magnitude.
In 6 secs, the dog covers-
S=vt
8.9*6 = 53.4 m.
In the same time, the cat covers, 53.4-3.8 = 49.6 m.
Thus, speed of the cat, v= s/t,
= 49.6/6 = 8.267 m/s
c) only from warmer areas to colder areas.
The second principle of thermodynamics states that heat can only flow from a hotter body to a cooler one. Specifically, Clausius statement says that is not possible for heat to move by itself from a lower temperature body to a higher temperature body.
