Answer:
The coefficient of linear expansion
\°C
Explanation:
Given initial temperature
°C
And final temperature
°C
Initial length 
Final length 
We have to find the coefficient of linear expansion
The coefficient of linear expansion is defined as the change in length per unit original length divide by the change in temperature.

So,
\°C
Answer:
P.E = 13230 J
Explanation:
Given,
The mass of the rock, m = 45 Kg
The rock is sitting at a height from the ground, h = 30 m
The acceleration due to gravity, g = 9.8 m/s²
The potential energy of the body is given by the formula,
P.E = mgh joules
Substituting the given values in the above equation
P.E = 45 x 9.8 x 30
= 13230 J
Hence, the potential energy of the rock is P.E = 13230 J
Answer:
20m/s
Explanation:
it covers 20 metres in a second
Argon<span> gas is used in fluorescent and incandescent light </span>bulbs<span> to stop the oxygen in the light </span>bulbs<span> from corroding the hot tungsten filament.The use of </span>argon<span> in light</span>bulbs<span> prevents the evaporation of the tungsten filaments, which results in increased light </span>bulb<span> life.</span>