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 :
Explanation:
The Coulomb's law states that the magnitude of each of the electric forces between two point-at-rest charges is directly proportional to the product of the magnitude of both charges and inversely proportional to the square of the distance that separates them:
In this case we have an electron (-e) and a proton (e), so:
In this case, the electric force is negative, therefore, the force is repulsive and its magnitude is:
Answer:
thats a lot, which one u want me to do?
Explanation:
Answer:
the car have travelled 0.31 mile during that time
Explanation:
Applying the Equation of motion;
s = 0.5(u+v)t
Where;
s = distance travelled
u = initial speed = 0 mph
v = Final speed = 50 mph
t = time taken = 3/4 min = 3/4 ÷ 60 hours = 1/80 hour
Substituting the given values into the equation;
s = 0.5(0+50)×(1/80)
s = 0.3125 miles
s ~= 0.31 mile
the car have travelled 0.31 mile during that time
