Time period of pendulum is given by

Here,
L is length
g is acceleration due to gravity
Therefore we can determine that the period of the pendulum is directly proportional to the square root of the length of the rope.

Therefore, it is necessary to increase the length of the rope to increase the period so that it counts the seconds more slowly. The correct answer is A.
Answer:
D. Molecules of a gas slow down and change to a liquid state.
Explanation:
- Condensation refers to a process by which a gas changes from gaseous state to liquid state. For example, water vapor changes to from the state of being a gas to liquid state water.
- Condensation is the opposite of evaporation and occurs when gaseous particles slow down and change into liquid state.
- Heat energy is lost during condensation and gaseous molecules lose kinetic energy making them to slow down and thus changing to liquid state,
Answer:
(a) Ratio of mean density is 0.735
(b) Value of g on mars 0.920 
(c) Escape velocity on earth is 
Explanation:
We have given radius of mars
and radius of earth 
Mass of earth 
So mass of mars 
Volume of mars 
So density of mars 
Volume of earth 
So density of earth 
(A) So the ratio of mean density 
(B) Value of g on mars
g is given by 
(c) Escape velocity is given by

Color is what scientist use to determine the temperature of a star!
hope this helps!