Answer:
135 hour
Explanation:
It is given that a carburizing heat treatment of 15 hour will raise the carbon concentration by 0.35 wt% at a point of 2 mm from the surface.
We have to find the time necessary to achieve the same concentration at a 6 mm position.
we know that 
where x is distance and t is time .As the temperature is constant so D will be also constant
So 
then 
we have given 
and we have to find 
putting all these value in equation
so 
Answer:
Atlantis benefited from lessons learned in the construction and testing of Enterprise, Columbia and Challenger. ... The Experience gained during the Orbiter assembly process also enabled Atlantis to be completed with a 49.5 percent reduction in man hours (compared to Columbia).
Explanation:
Answer:
Explanation:
We use kinetic friction when a body is moving i.e. for calculations.
Static friction is used when a body is in rest while kinetic friction is used when a body is moving and its value is quite low as compared to static friction .
Static friction value increases as we apply more force while kinetic friction occurs when there is relative motion between bodies.
