There are three forces `F_(1) F_(2)` and `F_(3)` acting on a body, all acting on a point P on the body. The body is found to move with uniform speed.
(a) Show that the forces are coplanar.
(b) Show that the torque acting on the body about any point due to these three forces is zero.

Explanation

As shown in figure three forces `F_(1) F_(2) F_(3)` act at point P on body

( a) Figure shows that forces are in same plane that is forces are coplaner body moves with constant uniform speed (velocity )
`f= ma`
`-m (c )`
`F_(1) + F_(2) + F_(3) = 0`
(b ) Calculating torque of these forces about point P .As forces passes through P torque about point P is zero .