Two poles are connected by a wire that is also connected to the ground. The first pole is 20ft tall and the second pole is 10ft
tall. There is a distance of 30ft between the two poles. Where should the wire be anchored to the ground to minimize the amount of wire needed
1 answer:
Answer: 31.6ft
Explanation:
Check the attachment for the diagram.
According to the right angle triangle AEC, we will use Pythagoras theorem to get |AC|. Note that |AE| = |AB| - |CD|
that is 20ft - 10ft = 10ft
According to the theorem, the square of the sum of the adjacent side and the opposite side is equal to the square of the hypotenuse.
|AE|^2 + |EC|^2 = |AC|^2
10^2 + 30^2 = |AC|^2
100 + 900 = |AC|^2
|AC| = √1000
|AC| = 31.6ft
Therefore, the wire should be anchored 31.6ft to the ground to minimize the amount of wire needed.
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Answer:
(a) W=1.20×10⁴J
(b) U= -5.46×10⁴J
(c) Q= -4.26×10⁴J
Explanation:
Given that student does 1.20×10⁴J work
(a) W=1.20×10⁴J
Work done by student,so positive sign
During the process, his internal energy decreases by 5.46×10⁴J.
(b) U= -5.46×10⁴J.
As the Energy decreases therefore negative sign
For (c) Q
We know the formula
Answer:
Explanation:
Torque, is given by
where F is force and r is perpendicular distance
where
is the angle of inclination
Torque, can also be found by
where I is moment of inertia and a is angular acceleration
Therefore, Fr=Ia and F=mg where m is mass and g is acceleration due to gravity
Making a the subject, and already I is given as
hence
Taking g as 9.81, is given as 37 and L is 1.2
Answer:
125.83672 seconds
Explanation:
P = Power of the horse = 1 hp = 746 W (as it is not given we have assumed the horse has the power of 1 hp)
m = Mass of professor = 103 kg
g = Acceleration due to gravity = 9.8 m/s²
h = Height of professor = 93 m
Work done would be equal to the potential energy
Power is given by
The time taken by the horse to pull the professor is 125.83672 seconds