Answer:
A) against the breeze at 2 m/s
Explanation:
Given that air is blowing at 2 m/s.An a mosquito eat lunch.If mosquito want to eat lunch he have to move opposite to the direction of air because air is blowing at 2 m/s.So we can say that mosquito have to move against the air.
But in we have to protect our self from mosquito because if any mosquito bite us then it may lead to fever .So the protection is very important from mosquito .
Therefore the answer is --
A
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Answer:
<h2>Total thermal energy for all air molecules is 59.54 J</h2>
Explanation:
As we know that the ball comes to rest finally so here we can say that
initial total potential energy of the ball is transferred to the air molecules
So here we have


So here we have

So all the gravitational potential energy of the ball will convert into thermal energy of air molecules which is equal to 59.54 J
Answer:
Explanation:
Initially no of atoms of A = N₀(A)
Initially no of atoms of B = N₀(B)
5 X N₀(A) = N₀(B)
N = N₀ 
N is no of atoms after time t , λ is decay constant and t is time .
For A
N(A) = N(A)₀ 
For B
N(B) = N(B)₀ 
N(A) = N(B) , for t = 2 h
N(A)₀
= N(B)₀ 
N(A)₀
= 5 x N₀(A) 
= 5 
= 5 
half life = .693 / λ
For A
.77 = .693 / λ₁
λ₁ = .9 h⁻¹
= 5 
Putting t = 2 h , λ₁ = .9 h⁻¹
= 5 
= 30.25
2 x λ₂ = 3.41
λ₂ = 1.7047
Half life of B = .693 / 1.7047
= .4065 hours .
= .41 hours .