Is it possible to move in a curved path in the absence of a net force?

Are the paths of electrons straight lines between successive collisions (with the positive ions of the metal) in the (i) absence of electric field, (ii) presence of electric field ?

Consider the uniform magnetic field shown: Starting from point P and without leaving the region of magnetic field, is it possible to choose a closed path (that is, a path that returns to P) for which the line integral of the magnetic field is nonzero?

Think of situation when an obejct gets displaced in the absence of a force acting on it.

A particle 'P' is moving on a circular path under the action of only one force action always toward the fixed point 'O' on the circumference. Find the ratio of (d^(2)theta)/(dt^(2)) & (("d"theta)/(dt))^(2)

Is it possible to double the length of a metallic wire by applying force over it ?

An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?