Torque multiple choice question needing explanation

AI Thread Summary
When two equal forces act on a hinged object, the torque produced depends on both the distance from the pivot and the angle at which the force is applied. The equation T = r x F indicates that torque is a vector quantity, meaning direction matters. The initial assumption that greater distance always results in greater torque is incorrect without considering the angle of the forces. The correct answer to the question is false, as torque can be equal despite differing distances if the angle compensates. Understanding torque as a vector cross-product clarifies this concept.
wolk
Messages
3
Reaction score
0

Homework Statement



If two forces of equal magnitude act on an object that is hinged at a pivot, the force acting farther from the pivot must produce the greater torque about the pivot.

a. False
b. unable to decide without knowing shape of object
c. True

Homework Equations



T=rxF


The Attempt at a Solution



My logic told me that a greater distance r from the point of rotation equals a greater torque. The above equation makes this obvious. So I selected true and got marked incorrect, the answer is false. I feel that I was right or the question is misleading at best. Anyone care to weigh in?

thanks.
 
Physics news on Phys.org
Welcome to Physics Forums.

The expression "r x F" is not simply "distance multiplied times force". Do you see what the difference is?
 
uh, Obviously not. Does it have to do with it being a vector cross-product equation?
 
I think I get it now. Thank you for your generous and abundant guidance.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Thread 'A bead-mass oscillatory system problem'
I can't figure out how to find the velocity of the particle at 37 degrees. Basically the bead moves with velocity towards right let's call it v1. The particle moves with some velocity v2. In frame of the bead, the particle is performing circular motion. So v of particle wrt bead would be perpendicular to the string. But how would I find the velocity of particle in ground frame? I tried using vectors to figure it out and the angle is coming out to be extremely long. One equation is by work...
Back
Top