Hard woods and tight curves should be cut using what blade speeds.
1 answer:
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Answer:
2800 [MPa]
Explanation:
In fracture mechanics, whenever a crack has the shape of a hole, and the stress is perpendicular to the orientation of such, we can use a simple formula to calculate the maximum stress at the crack tip
Where is the magnitude of he maximum stress at the tip of the crack,
is the magnitude of the tensile stress,
is
the length of the internal crack, and
is the radius of curvature of the crack.
We have:
We replace:
We get:
Answer:
Explanation:
Given
--- Initial altitude
-- Altitude after 16.5 seconds
--- Acceleration (It is negative because it is an upward movement i.e. against gravity)
Solving (a): Final Speed of the rocket
To do this, we make use of:
The final altitude after 16.5 seconds is represented as:
Substitute the following values:
and
So, we have:
Collect Like Terms
Make u the subject
Solving (b): The maximum height attained
First, we calculate the time taken to attain the maximum height.
Using:
At the maximum height:
--- The final velocity
So, we have:
Collect Like Terms
Make t the subject
The maximum height is then calculated as:
This gives:
Hence, the maximum height is 1141.07ft