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.

There are three forces F_(1) F_(2) and F_(3) acting on a body, all act

1.	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.
Answer» Solution :As showninfigurethreeforces`F_(1)F_(2) F_(3)` act atpointP on body ( a) Figureshowsthat forces arein same planethat isforces arecoplanerbodymoveswithconstantuniform SPEED(velocity ) `F= ma` `-m (c )` `F_(1)+ F_(2)+ F_(3) = 0` (B )Calculatingtorque of these forcesaboutpointP .Asforcespassesthrough Ptorqueaboutpoint P is zero .