The answer is B............
The temperature of the water and copper beaker be together is 29.6⁰C.
<h3>
What is the equilibrium temperature of both substance?</h3>
The final temperature or equilibrium temperature of the water and copper beaker is calculated by applying the principle of conservation of energy.
Heat lost by the water = Heat gained by the copper beaker
mcΔθ (water) = mcΔθ (copper)
where;
- m is mass
- c is specific heat capacity
- Δθ is change in temperature
m₁c₁(T₁ - T) = m₂c₂(T - T₂)
where;
- T₁ is the initial temperature of water
- T₂ is the initial temperature of copper beaker
- T is the equilibrium temperature
Specific heat capacity of copper, c₂ = 389 J/kgK
Specific heat capacity of water , c₁ = 4200 J/kgK
(2)(4200)(30 - T) = (1)(389)(T - 20)
252,000 - 8400T = 389T - 7780
259,780 = 8789T
T = 259,780 /8789
T = 29.6⁰C
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Answer:
10.93m/s with the assumption that the water in the lake is still (the water has a speed of zero)
Explanation:
The velocity of the fish relative to the water when it hits the water surface is equal to the resultant velocity between the fish and the water when it hits it.
The fish drops on the water surface vertically with a vertical velocity v. Nothing was said about the velocity of the water, hence we can safely assume that the velocity if the water in the lake is zero, meaning that it is still. Therefore the relative velocity becomes equal to the velocity v with which the fish strikes the water surface.
We use the first equation of motion for a free-falling body to obtain v as follows;
v = u + gt....................(1)
where g is acceleration due to gravity taken as 9.8m/s/s
It should also be noted that the horizontal and vertical components of the motion are independent of each other, hence we take u = 0 as the fish falls vertically.
To obtain t, we use the second equation of motion as stated;

Given; h = 6.10m.
since u = 0 for the vertical motion; equation (2) can be written as follows;

substituting;

Putting this value of t in equation (1) we obtain the following;
v = 0 + 9.8*1.12
v = 10.93m/s
Answer:
b. 
Explanation:
As we know that the electric field due to infinite line charge is given as

here we can find potential difference between two points using the relation

now we have

now we have

now plug in all values in it


now we know by energy conservation

