Question

Suppose you are waiting for your friends on the platform of Kota station. The train approaches the
station with constant speed of 108 km/h. Your mass is 50 kg. Mark the correct options)[ ]
a) Your kinetic energy is zero
b) Your kinetic energy measured by your friend is 22500 I
c) Your kinetic energy measured by your friend is zero
d) None of the above​

Answer 1

The correct options are a)  Your kinetic energy is zero and b) Your kinetic energy measured by your friend is 22500.

• The kinetic energy of a matter is the energy possessed by it due to its motion. KE = 1/2 m v².
• Since velocity is a relative term, so is the kinetic energy. What may appear at rest to one person may appear in motion to another.
• In the given case, our absolute velocity is zero hence the absolute KE = 0.
• When seen from inside a train, we appear to move in the opposite direction with a speed of 108km/h (= 30m/s).
• The relative KE when seen from the train = 1/2 X 50 X 30 X 30 = 22500J.