football hemets have pads that are filled with air and thick foam so when they are hit the foam asorbs the hit and the air keeps the hard outer shell of the helmet from hiting the players head
it cannot be reuse and replaced for long period of time.hope it helps u
Answer:
Precisely, water has to absorb 4,184 Joules of heat (1 calorie) for the temperature of one kilogram of water to increase 1°C. For comparison sake, it only takes 385 Joules of heat to raise 1 kilogram of copper 1°C.
Explanation:
Answer:
The diameter of wire should be 
m
Explanation:
Given:
Current density 
Current 
A
From the formula of current density,
Where 
area of cylindrical wire = 
m
For finding the diameter of wire,
m
Therefore, the diameter of wire should be m
