Answer:
1.8m
Explanation:
Let the Elastics of the steel ASTM-36 
The strain of the bar when subjected to 150 MPa is

Therefore, if the bar elongates by 1.35 mm, then the original length L would be:

or 1.8m
Answer:
0.074m/s
Explanation:
We need the formula for conservation of momentum in a collision, this equation is given by,

Where,
= mass of ball
= mass of the person
= Velocity of ball before collision
= Velocity of the person before collision
= velocity of ball afer collision
= velocity of the person after collision
We know that after the collision, as the person as the ball have both the same velocity, then,


Re-arrenge to find
,

Our values are,
= 0.425kg
= 12m/s
= 68.5kg
= 0m/s
Substituting,


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<em>The speed of the person would be 0.074m/s after the collision between him/her and the ball</em>
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