Answer:
The deceleration is 
Explanation:
From the question we are told that
The height above firefighter safety net is 
The length by which the net is stretched is 
From the law of energy conservation

Where
is the kinetic energy of the person before jumping which equal to zero(because to kinetic energy at maximum height )
and
is the potential energy of the before jumping which is mathematically represented at

and
is the kinetic energy of the person just before landing on the safety net which is mathematically represented at

and
is the potential energy of the person as he lands on the safety net which has a value of zero (because it is converted to kinetic energy )
So the above equation becomes

=> 
substituting values

Applying the equation o motion

Now the final velocity is zero because the person comes to rest
So



Answer:
Making the lumber thick will make it stiff, which seems good. On the other hand, with thicker lumber, differences in expansion on the two faces have more leverage to make the lumber move.
Answer:
The Forces of Flight
At any given time, there are four forces acting upon an aircraft.
These forces are lift, weight (or gravity), drag and thrust. Lift is
the key aerodynamic force that keeps objects in the air. It is the
force that opposes weight; thus, lift helps to keep an aircraft in
the air. Weight is the force that works vertically by pulling all
objects, including aircraft, toward the center of the Earth. In order
to fly an aircraft, something (lift) needs to press it in the opposite
direction of gravity. The weight of an object controls how strong
the pressure (lift) will need to be. Lift is that pressure. Drag is a
mechanical force generated by the interaction and contract of a
solid body, such as an airplane, with a fluid (liquid or gas). Finally,
the thrust is the force that is generated by the engines of an
aircraft in order for the aircraft to move forward.
Explanation: