What is the nature of velocity-time graph for a car moving with uniform acceleration?

The correct answer is C, Straight line. With uniform acceleration, velocity changes by the same amount in every equal interval of time, so the velocity-time graph is a straight line whose slope equals the acceleration. The first equation of motion, v = u + at, has the same form as the equation of a straight line, with the initial velocity u as the intercept and the acceleration a as the slope. A steeper line means a larger acceleration, a line sloping down means uniform retardation, and a horizontal line means constant velocity. The area under a velocity-time graph gives the displacement in that time. Option A is wrong because a parabola is the shape of the position-time graph, not the velocity-time graph, for uniformly accelerated motion, since s = ut + ½at². Option B is wrong because a logarithmic curve would mean the velocity grows ever more slowly, which is not uniform acceleration. Option D is wrong because an exponential curve would mean the velocity grows ever faster, so the acceleration itself would be rising. Exam tip: uniform acceleration gives a straight-line v-t graph and a parabolic s-t graph; slope of v-t = acceleration, area = displacement.