Answer:
The rate of change of the area when the bottom of the ladder (denoted by 
) is at 36 ft. from the wall is the following:
Explanation:
The Area of the triangle is given by 
where 
(by using the Pythagoras' Theorem) and is the length of the base of the triangle or the distance between the bottom of the ladder and the wall.
The area is then
The rate of change of the area is given by its time derivative
Product rule
Chain rule
In here we can identify 
, 
and 
.
The result is then
Answer:
D) True. This is what creates the body weight
Explanation:
Let's write Newton's second law for this case. For inclined planes the reference system takes one axis parallel to the plane (x axis) and the other perpendicular to the plane (y axis)
X axis
Wx -fr = ma
Y Axis
N - Wy = 0
With trigonometry we can find the components of weight
sin θ = Wₓ / W
cos θ = 
/ W
Wₓ = W sin θ
= W cos θ
W sin θ - fr = ma
From this expression as it indicates that the body is descending the force greater is the gravity that create the weight of the body
Let's examine the answers
A False This force does not apply because it is not a spring
B) False. It is balanced at all times with the component (Wy) of the weight
C) False. For there to be a rope, if it exists you should be less than the weight component for the block to lower
D) True. This is what creates the body weight
E) False. The cutting force occurs for force applied at a single point and gravity is applied at all points
