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:
1.F: About 6*10^14 Hz
2.E: About 4*10^ -19 J
Explanation:
Frequency: We knew that the speed of a wave is its wavelength(λ)* frequency(f, in Hz). By the wave-particle duality we know we can calculate the frequency of light in the same way. So, c=495nm *f, f=c/495nm=> (299,792,458 m/s) / (4.95*10^-7 m)
=6.05*10^14 /s
Energy: The energy photon contains can be calculate by this formula-- E=hf
f is the frequency and h is Planck's constant which is about 6.62 ×10^-34 *m^2*kg/s (after dimensional analysis ) =6.62*10^ -34 J*s.
So, the energy of a blue photon is (6.05*10^14)*(6.62*10^-34)=40.051*10^-20= 4.051*10^-19 J
The loudness was increased by the amplifier which converted electrical energy into sound energy.
Answer:
Final velocity v=19.83 m/sec
Explanation:
We have given initial velocity u =5.13 m/sexc
Acceleration of automobile 
Time t =4.9 sec
We have to find the final velocity v
According to first law of motion v = u+at ,here v is the final velocity , a is acceleration and t is time
So 
So the final velocity is 19.83 m/sec