Calculating Torque: How to Find Torque with Vector r, Acceleration a, and Mass m

Thread starter nameVoid
Start date Dec 3, 2010
Tags

Torque

AI Thread Summary

Torque can be calculated using the formula τ = r × (ma), where r is the position vector, m is the mass, and a is the acceleration vector. This calculation provides the torque about the origin due to the net force acting on the object. The net force is aligned with the direction of acceleration. The discussion confirms that this method is valid at the instant considered. Understanding this relationship is crucial for analyzing rotational dynamics.

Dec 3, 2010

nameVoid

an object at vector r has acceleration vector a and mass m can u find torque About the origin by taking r cross (ma) sorry on cell phone

Physics news on Phys.org

Dec 3, 2010

PhanthomJay

Science Advisor

Homework Helper

Insights Author

At that instant, yes, that would be the torque of the net force acting on the object, about the origin, with net force in direction of acceleration.

Thread 'I've come across another fluid pressure problem I don't understand'

Neglect gravity other than that of water; neglect friction. F1=ρgsh=1000*10*1*(1+4)=50000 N; F1=ρgsh=1000*10*0.1*4=4000 N; F3=50000-4000=46000 N?

View full post »

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...

View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

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...

View full post »