Answer:
While the bus is moving, luggage tends to remain in inertia of motion state. When the bus stops, the luggage tends to resist the change and due to inertia of motion it moves forward and may fall off. That's why it is advised to tie any luggage kept on the roof of a bus with a rope.
As we know the formula of kinetic energy is

here given that
KE = 150,000 J
mass = 120 kg
we can use this to find speed



So speed of above object is 50 m/s
Water as it's the highest specific heat capacity
Hope this helps x
V = f * wavelength
as we know electromagnetic wave has speed equal to light, so
3 * 10^8 = f * 1.3
f = 2.3 * 10^8 hertz
f = 230 mega hertz