Answer:
(a) The kinetic energy in joules is 194400 J
(b) The energy in calories is 46462.72 calories
(c) When the automobile brakes to a stop, the energy will decrease to 0 J.
Explanation:
(a) Kinetic energy (K.E) is given by the formula below

Where K.E is the kinetic energy in Joules (J)
is the mass in kilogram (kg)
is the velocity in meter per second (m/s)
From the question,
1200 kg
18 m/s
Hence,
becomes

J
This is the energy is joules
(b) To convert this energy to calories (cal)
4.184 J = 1 cal
Then, 194400 J =
cal

cal
K.E = 46462.72 calories
This is the energy in calories
(c) When the automobile brakes to a stop, the energy will decrease to 0 J.