<u>Answer</u>
3 Ohms
<u>Explanation</u>
when the resistors are in series, the resistance in the circuit increases. For example, if two resistors, R1 and R2 are in series, the combined resistance is R1+R2.
When connected in parallel, the total resistance is the reciprocal of (1/R1 + 1/R2)
In this case the resistors are in parallel.
Total resistance = (1/12 + 1/4)⁻¹
= (1/3)⁻¹
= 3 Ohms
0.0605J is your answer. Use the formula KE=1/2mv^2
Answer : The temperature when the water and pan reach thermal equilibrium short time later is, 
Explanation :
In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.


where,
= specific heat of aluminium = 
= specific heat of water = 
= mass of aluminum = 0.500 kg = 500 g
= mass of water = 0.250 kg = 250 g
= final temperature of mixture = ?
= initial temperature of aluminum = 
= initial temperature of water = 
Now put all the given values in the above formula, we get:


Therefore, the temperature when the water and pan reach thermal equilibrium short time later is, 