Can there be a motion in two dimensions with an acceleration only in one direction?

Relative motion in 2 dimensions

Projectile motion is a two dimensional motion with constant acceleration. Is this statement true or false?

Assertion : The equation of motion can be applied only if acceleration is along the direction of velocity and is constant. Reason : If the acceleration of a body is constant then its motion is known as uniform motion.

Discuss the general relations for velocity and acceleration for motion of an one dimension in a plane.

Assertion: For motion in two or three diemensions, velocity and acceleration vecotrs must have any angle between 0^(@) and 90^(@) between them. Reason: For such motion velocity and acceleration of an object is always in the opposite direction.

An object is moving due north with an acceleration in that direction. From only this information one can conclude

Projectile motion is a combination of two one-dimensional motion: one in horizontal and other in vertical direction. Motion in 2D means in a plane. Necessary condition for 2D motion is that the velocity vector is coplanar to the acceleration vector. In case of projectile motion, the angle between velocity and acceleration will be 0^@ltthetalt180^@ . During the projectile motion, the horizontal component of velocity ramains unchanged but the vertical component of velocity is time dependent. Now answer the following questions: A particle is projected from the origin in the x-y plane. The acceleration of particle in negative y-direction is alpha . If equation of path of the particle is y = ax - bx^2 , then initial velocity of the particle is