The vector sum of a system of non-collinear forces acting on a rigid body is gives to be non-zero. If the vector sum of all the torques due to the system of forces about a certain point is found to be zero, does this mean that it is necessarily zero about any arbitrary point?

These are three forces F_1, F_2,F_3 acting on a body, all acting on a point P on the body. the body is found to move with uniform speed. Show that the torque acting on the body about any point due to these three forces is zero.

A force of magnitude 6 acts along the vector (9, 6, -2) and passes through a point A(4, -1,-7) . Then moment of force about the point O(1, -3, 2) is

Supose a gaussian surface does not include any net charge. Does it necessarily mean that E is equal to zero for all points on the surface?

Show by giving an example that if force acting in the body does not produce any displacement then the work done will be zero ?

If veca,vecb,vecc are three non-zero vectors such that each one of these is perpendicular to the sum of the other two vectors, then the value of |veca+vecb+vecc|^2 is :

Electric field is the electrostatic force per unit charge acting on a vanishingly small test charge placed at that point. It is a vector quantity and the electric field inside a charged conductor is zero. Electric flux f is the total number of electric lines of force passing through a surface in a direction normal to the surface when the surface is placed inside the electric field We have a Gaussian of radius R with Q at the centre then

A force F=2hat(i)+hat(j)-hat(k) acts at point A whose position vector is 2hat(i)-hat(j) . Find the moment of force F about the origin.

Different points in earth are at slightly different distancesfrom the sun and hence experience different forces due to gravitation. For a rigid body, we know that if various forces act at various points in it, the resultant motion is as if a net force acts on the C.M. (centre of mass ) causing rotation around an axis thorugh the C.M. For the earth-sun system (approximating the earth as a uniform density sphere)