Answer: Yes
Explanation:
does hot air rise
er substances, expands when heated and contracts when cooled. Because there is more space between the molecules, the air is less dense than the surrounding matter and the hot air floats upward. This is the concept used in the hot air balloons.
Answer:


Explanation:
A denotes Alex
M denotes Mary
r = Distance from center
Mary and Alex will have the equal displacements in equal interval of time as they are in uniform circular motion. So,

Tangential speed speed is given by

The tangential speed of Mary is 
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- m is mass, and its units are kg
- k is the elastic constant measured in newtons per meter (N/m), or kilograms per second squared kg/s²
Therefore:
![\sqrt{\dfrac{m}{k}} =\sqrt{\dfrac{[kg]}{[\dfrac{kg}{s^2}]}} =\sqrt{\dfrac{[kg]}{[kg]}\cdot s^2} = \sqrt{[s]^2} = s](https://tex.z-dn.net/?f=%5Csqrt%7B%5Cdfrac%7Bm%7D%7Bk%7D%7D%20%3D%5Csqrt%7B%5Cdfrac%7B%5Bkg%5D%7D%7B%5B%5Cdfrac%7Bkg%7D%7Bs%5E2%7D%5D%7D%7D%20%20%3D%5Csqrt%7B%5Cdfrac%7B%5Bkg%5D%7D%7B%5Bkg%5D%7D%5Ccdot%20s%5E2%7D%20%3D%20%5Csqrt%7B%5Bs%5D%5E2%7D%20%3D%20s)
The period is given in seconds so the formula is dimensionally correct.
Answer:
t₁ > t₂
Explanation:
A coin is dropped in a lift. It takes time t₁ to reach the floor when lift is stationary. It takes time t₂ when lift is moving up with constant acceleration. Then t₁ > t₂, t₁ = t₂, t₁ >> t₂ , t₂ > t₁
Solution:
Newton's law of motion is given by:
s = ut + (1/2)gt²;
where s is the the distance covered, u is initial velocity, g is the acceleration due to gravity and t is the time taken.
u = 0 m/s, t₁ is the time to reach ground when the light is stationary and t₂ is the time to reach ground when the lift is moving with a constant acceleration a.
hence:
When stationary:

Hence t₂ < t₁, this means that t₁ > t₂.
1 is b high birth rate and death rate 2 is a low birth rates death are constant and 3 is c high birth rate and low death rate
Explanation: