The main reason why wheelchair ramps are used to move people up a staircase is because it has a high mechanical advantage which leads to a greater efficiency in moving people up the staircase.
- <em>Let the height of the staircase = h</em>
- <em>Let the length of the ramp = L</em>
The mechanical advantage of the ramp is calculated as follows;

As the length of the ramp increases, people will be move up to a greater distance up the staircase.
Thus, the main reason why wheelchair ramps are used to move people up a staircase is because it has a high mechanical advantage which leads to a greater efficiency in moving people up the staircase.
Learn more about mechanical advantages of ramps here: brainly.com/question/200179
(a) 24.6 Nm
The torque produced by the net thrust about the center of the circle is given by:

where
F is the magnitude of the thrust
r is the radius of the wire
Here we have
F = 0.795 N
r = 30.9 m
Therefore, the torque produced is

(b) 
The equivalent of Newton's second law for a rotational motion is

where
is the torque
I is the moment of inertia
is the angular acceleration
If we consider the airplane as a point mass with mass m = 0.741 kg, then its moment of inertia is

And so we can solve the previous equation to find the angular acceleration:

(c) 
The linear acceleration (tangential acceleration) in a rotational motion is given by

where in this problem we have
is the angular acceleration
r = 30.9 m is the radius
Substituting the values, we find

Answer:
0 J
Explanation:
The mechanical energy of a spring is given by
where k is spring constant and x is extension of spring. Since the spring is unstretched, its extension is zero.
#Notice that the potential energy is 0.
-Substituting spring constant, k with 8 and extension with zero then the mechanical energy will be

<h3>formula of speed is distance/time</h3><h3>so</h3><h2>140/2.5</h2><h2>= 56</h2><h2>the answer should be </h2><h2>56 km/h</h2>