Solving Torque Problem: Find Forces FT, Horizontal & Vertical on Beam

  • Thread starter Thread starter xregina12
  • Start date Start date
  • Tags Tags
    Torque
Click For Summary
SUMMARY

The discussion focuses on solving a torque problem involving a floodlight with a mass of 40 kg supported by a horizontal beam and a cable at an angle of 11° to the beam. The force FT provided by the cable is calculated to be 2056 N. The user successfully determined the horizontal force exerted on the beam by the pole but struggled with calculating the vertical force (Fy). The equations used include Fynet=0 and \sumτ=\tau_1+\tau_2, leading to confusion regarding the vertical force's value.

PREREQUISITES
  • Understanding of torque and equilibrium in physics
  • Knowledge of trigonometric functions, specifically sine
  • Familiarity with Newton's laws of motion
  • Basic skills in solving algebraic equations
NEXT STEPS
  • Review the principles of static equilibrium in physics
  • Learn about torque calculations and their applications
  • Study the use of trigonometric functions in force resolution
  • Explore examples of similar problems involving beams and forces
USEFUL FOR

Students studying physics, engineers working with structural mechanics, and anyone interested in understanding forces acting on beams and static systems.

xregina12
Messages
26
Reaction score
0
A floodlight with a mass of 40 kg is used to
illuminate the parking lot in front of a library.
The floodlight is supported at the end of a
horizontal beam that is hinged to a vertical
pole, as shown. A cable thatmakes an angle of
11◦ with the beam is attached to the pole to
help support the floodlight. Assume the mass
of the beam is negligible when compared with
the mass of the floodlight.
The acceleration of gravity is 9.81 m/s2 .

a) Find the force FT provided by the cable.
Answer in units of N.
2056 N
b) Find the horizontal force exerted on the
beam by the pole. Answer in units of N.

c) Find the vertical force exerted on the beam
by the pole. Answer in units of N.


I got a and b but for some reason I can't get c.
My work.
Fynet=0=Tsin11+Fy-mg where Fy is the vertical force exerted on the beam by the pole.
Tsin11+Fy=mg
392.4 +Fy=392.4
Fy=0
however, that doesn't work
anyone has suggestions for part c?
 
Physics news on Phys.org
xregina12 said:
A floodlight with a mass of 40 kg is used to
illuminate the parking lot in front of a library.
The floodlight is supported at the end of a
horizontal beam that is hinged to a vertical
pole, as shown. A cable thatmakes an angle of
11◦ with the beam is attached to the pole to
help support the floodlight. Assume the mass
of the beam is negligible when compared with
the mass of the floodlight.
The acceleration of gravity is 9.81 m/s2 .

a) Find the force FT provided by the cable.
Answer in units of N.
2056 N
b) Find the horizontal force exerted on the
beam by the pole. Answer in units of N.

c) Find the vertical force exerted on the beam
by the pole. Answer in units of N.


I got a and b but for some reason I can't get c.
My work.
Fynet=0=Tsin11+Fy-mg where Fy is the vertical force exerted on the beam by the pole.
Tsin11+Fy=mg
392.4 +Fy=392.4
Fy=0
however, that doesn't work
anyone has suggestions for part c?

\sum\tau=\tau_1+\tau_2=r\vec{w}+r\vec{T}\rightarrow\vec{w}=-\vec{T}\sin(11\pi/180)\rightarrow\vec{T}=2057N.

Then, we notice that \sin(11\pi/180)\cdot2057=392.5 and \vec{w}=392.4. So, maybe it's just that 0.10N that they're worrying about? IDK.
 

Similar threads

Replies
8
Views
6K
Replies
6
Views
2K
  • · Replies 42 ·
2
Replies
42
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 9 ·
Replies
9
Views
5K
  • · Replies 1 ·
Replies
1
Views
4K
Replies
12
Views
4K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 14 ·
Replies
14
Views
3K