Below are some common student misconceptions about the concept of forces:

An object will slow down if there is no net force. (description) (discover) (references)

The motion will follow the path of the stronger force on the object. (description) (discover) (references)

Passive forces don't exist (tables don't exert a normal force). (description) (discover) (references)

Normal forces won't exceed the weight (active force) on an object. (description) (discover) (references)

An object with a constant (non-zero) net force will have a constant speed. (description) (discover) (references)

Faster moving objects have a larger force acting on them. (description) (discover) (references)

A constant force accelerates a body, until the body uses up all the power of the force. (description) (discover) (references)

The net force must be in the direction of motion, so objects will travel along a line in that direction. (description) (discover) (references)

Objects can be trained to follow a certain path by forces, and will continue along that path, even after the forces are removed. (description) (discover) (references)

Heavier objects fall faster than light objects. (description) (discover) (references)

Objects will point in the direction of their velocity. (description) (discover) (references)

Force must be positive, plotted above the time axis. (description) (discover) (references)

Strings transmit (unchanged) an external force acting on one object to another object. (description) (discover) (references)

The tension in a string is the sum of the forces acting on each end. (description) (discover) (references)