Which graph corresponds to an object moving with a constant negative acceleration and a positive velocity?

We want a motion with:

• positive velocity → graph stays above x-axis
• constant negative acceleration → velocity decreases uniformly

Using

$$v^2=u^2+2as$$

with a<0 velocity decreases with distance in a nonlinear (curved) way.

So the correct graph must:

• start at a positive velocity
• decrease continuously
• be curved (not a straight line)
• eventually approach zero

Graph (3) matches this:

• velocity is always positive
• it decreases with distance
• the curve bends downward (consistent with negative acceleration)

Why others are wrong:

• straight line → constant slope → would mean constant acceleration in v vs t, not v vs x
• increasing curve → implies positive acceleration

Final answer: Graph (3)