Equation for gravitational torque

Click For Summary
SUMMARY

The discussion centers on calculating the gravitational torque acting on a thin rod with mass M and length L, fixed at one end by a frictionless hinge. The correct torque when the rod is balanced vertically is zero, as there is no angular displacement to create torque. The user initially calculated torque as T = MgL but sought clarification on the fractions presented in the options. The confusion arises from the need to incorporate trigonometric functions in the torque calculation, specifically when considering the angle of the rod relative to the vertical.

PREREQUISITES
  • Understanding of torque and its calculation (Torque = Force x Distance)
  • Familiarity with gravitational force (F = Mg)
  • Basic knowledge of trigonometry and angles
  • Concept of angular displacement and its relation to torque
NEXT STEPS
  • Study the derivation of torque in rotational dynamics
  • Learn about the role of angles in torque calculations
  • Explore the concept of equilibrium in rigid body mechanics
  • Review examples of torque involving different angles and configurations
USEFUL FOR

Students studying physics, particularly those focusing on mechanics and torque calculations, as well as educators seeking to clarify concepts related to rotational motion.

alem
Messages
3
Reaction score
0

Homework Statement


A thin rod (uniform density and thickness)
with mass M and length L attached to floor at a fixed location by a frictionless hinge.

while balanced vertically the gravitational torque acting on the rod is
a.) zero
b.) 1/2 MgL
c.)1/3 MgL
d.)1/4 MgL
e.)1/6 MgL

Homework Equations



I know that torque is F x D(or L)
F=Ma
and a is g in this case,
so T= MgL

The Attempt at a Solution



as stated above I got to T=MgL
but I don't understand where the fractions are coming from? can someone please explain this?
 
Physics news on Phys.org
You forgot something when computing the cross product, there's a trig function in there somewhere ;)
 

Similar threads

Replies
7
Views
2K
  • · Replies 3 ·
Replies
3
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 17 ·
Replies
17
Views
2K
  • · Replies 15 ·
Replies
15
Views
4K
  • · Replies 2 ·
Replies
2
Views
6K
  • · Replies 21 ·
Replies
21
Views
5K
Replies
12
Views
11K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K