TORQUE- CENTRE OF GRAVITY
TORQUE- CENTRE OF GRAVITY
about an axis is called torque or momentum of force.“
force arm ( ) and the force ( ).
The turning effect of a force depends upon two factors:
Magnitude of force (F)
Magnitude of moment arm (r)
The torque about any axis is given by the product of force and moment arm.
Consider a particle of mass ‘m’ which is acted upon a force . Let be the position vector of the particle which is also the position vector of the point of application of force. We can resolve this force into two rectangular components:
1. Parallel to the position vector i.e. Or Fcosq
2. Perpendicular to the position vector i.e. Or Fsinq
From figure it is clear that can pull the particle but it cannot rotate it or it is unable to produce torque in the mass. It is the component which produces rotation in the mass.
Let r andbe the magnitude of and respectively.
The magnitude of of the torque produced about the centre ‘O‘ is defined as:
Where q is the smaller angle between the positive direction of and . Using vector notation, above expression can also be written as :
The direction of torque is directed along the normal to the plane formed by and as given by right hand rule.
Positive torque:
If a body rotates about its axis in anti clockwise direction, then the torque is taken positive . Negative torque:
If the body rotates in the clockwise direction, then the torque is taken as negative .
Let the position vector is = x i+ y j+ z k and the force= Fx i+ Fy j+ Fz k The torque is given by:
In SI system unit of torque is N-m ( Newton . Metre)
The torque or moment of force can be define as
about an axis is called torque or moment of force.“
The turning effect of a force depends upon two factors:
The magnitude of force (F)
Moment arm (r)
The torque about any axis is given by the product of force and moment arm
OR
Positive torque:
If a body rotates about its axis in anti clockwise direction, then the torque is taken positive . Negative torque:
If the body rotates in the clockwise direction, then the torque is taken as negative . For latest information , free computer courses and high impact notes visit :
Rectangle
Center of gravity of a rectangular is at the point of intersection of its diagonals
Circle
Center of gravity of a circle is at its center. Square
Center of gravity of square is at the point of intersection of its diagonals.
Regular bar
The center of gravity of a regular bar is at its geometrical center.
Triangle
The center of gravity of a triangle is at the point of intersection of its medians.
Cylinder
The center of gravity of a cylinder is at the axis of cylinder.