Question

define motion in a straight line with constant acceleration.

Answer 1

motion is change in position of object over a period of time 
if an object is moving with constant velocity then acceleration is zero
but if object is moving with uniform velocity(object covering equal displacement in equal intervals of time) then the acceleration is constant

Answer 2

Answer:

Explanation:

Linear motion also called rectilinear motion is a one-dimensional motion along a straight line, and can therefore be described mathematically using only one spatial dimension.