Answer : The final temperature 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 ice = 
= specific heat of water = 
= mass of ice = 50 g
= mass of water = 200 g
= final temperature = ?
= initial temperature of ice = 
= initial temperature of water = 
Now put all the given values in the above formula, we get:


Therefore, the final temperature is, 
Answer:
1800/300 = 6ropes
Explanation:
The engine weighs 1800N and the person exerts a force of 300N, so for him to lift the engine and exerting a force of 300N all through we divide the weight of the engine by the force exerted to know how many ropes are used. Which makes it 6 thereby each rope uses 300N to lift the engine.
Explanation:
(a) Since, it is given that the blocks are identical so distribution of charge will be uniform on both the blocks.
Hence, final charge on block A will be calculated as follows.
Charge on block A =
= 4.35 nC
Therefore, final charge on the block A is 4.35 nC.
(b) As it is given that the positive charge is coming on block A
. This means that movement of electrons will be from A to B.
Thus, we can conclude that while the blocks were in contact with each other then electrons will flow from A to B.