The old electricity meters with disk using sapphire bearings for friction to be minimal to not aggravate metering
Explanation:
It is given that,
Speed of the ball, v = 10 m/s
Initial position of ball above ground, h = 20 m
(a) Let H is the maximum height reached by the ball. It can be calculated using the conservation of energy as :


h' = 5.1 m
The maximum height above ground,
H = 5.1 + 20
H = 25.1 meters
So, the maximum height reached by the ball is 25.1 meters.
(b) The ball's speed as it passes the window on its way down is same as the initial speed i.e. 10 m/s.
Hence, this is the required solution.
Answer:
The discharge rate is 
Explanation:
From the question we are told that
The diameter is 
The head is 
The coefficient of contraction is 
The coefficient of velocity is 
The radius is mathematically evaluated as

substituting values


The area is mathematically represented as

substituting values


The discharge rate is mathematically represented as

substituting values


Answer: 2.67 m/s
Explanation:
Given
Mass of block A is 
mass of block B is 
The initial velocity of block A 
the initial velocity of block B is 
After collision velocity of block A is 
Conserving momentum

The momentum of block A after the collision is 
Therefore, there is no change in sign.