If force is always parallel to motion

If the force is always perpendicular to motion, then KE remains constant

Assertion: Force is always in the direction of motion. Reason: In every case force is not parallel to acceleration.

Name the force which always oppose motion.

A particle of mass m starts moving from origin along a horizontal x-y plane under the influence of a force of constant magnitude F ( which is always parallel to the x-axis ) and a constraint force. The trajectory of its motion is f ( x) = ( x)/( x^(2) + 1) . Then,

A particle of mass m starts moving from origin along a horizontal x-y plane under the influence of a force of constant magnitude F ( which is always parallel to the x-axis ) and a constraint force. The trajectory of its motion is f ( x) = ( x)/( x^(2) + 1) . Then,

Name the force which always opposes motion.

Assertion: Frictional force is the component of contact force parallel to the surface. Reason: Friction force always opposes the motion of a body.

Assertion: Frictional force is the component of contact force parallel to the surface. Reason: Friction force always opposes the motion of a body.

Assertion: Frictional force is the component of contact force parallel to the surface. Reason: Friction force always opposes the motion of a body.