There are four laws of thermodynamics.
Zeroeth Law of Thermodynamics: Two systems in thermal equilibrium with a third system are in thermal equilibrium to each other.
First Law of Thermodynamics: The change in a system's internal energy is equal to the difference between heat added to the system from its surroundings and work done by the system on its surroundings.
Second Law of Thermodynamics: It is impossible for a process to have as its sole result the transfer of heat from a cooler body to a hotter one.
Third Law of Thermodynamics: The entropy of a perfect crystal at absolute zero is exactly equal to zero.
Explanation:
u=54 km/h
54*5/18=15 m/s
v=0m/s
t=?
acceleration=-0.5m/s^2
we know that a=v-u/t
so,
t=v-u/a
t=15-0/0.5
=15/0.5
=30
therefore, the time is 30 second
Hope this answer helps you..
As we know that two charges exert force on each other when they are placed near to each other
The force between two charges is given as

here we know that
= two different point charges
r = distance between two point charges
also we know that two similar charges always repel each other while two opposite charges always attract each other
so here correct answer would be
<em>A. A positive and negative charge attract each other.</em>