The velocity of A is 5.16m/s²
<u>Explanation:</u>
Given-
mass of cylinder A, mₐ = 2kg
mass of cylinder B, mb = 10kg
Distance, s = 2m
Velocity of A, v = ?
Let acceleration due to gravity, g = 10m/s²
We know,

We know,


Therefore, the velocity of A is 5.16m/s²
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, 
Given :
The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12.
To Find :
How many grains are there in the ball?
Solution :
Volume of ball of the ballpoint is :

Now, grain size of 12 has about 520000 grains/mm³.
Therefore, number of grains are :
