## Quick Reference

A graph that shows acceleration plotted against time for a particle moving in a straight line. Let *v*(*t*) and *a*(*t*) be the velocity and acceleration, respectively, of the particle at time *t*. The acceleration-time graph is the graph *y*=*a*(*t*), where the *t*-axis is horizontal and the *y*-axis is vertical with the positive direction upwards. With the convention that any area below the horizontal axis is negative, the area under the graph between *t*=*t*_{1} and *t*=*t*_{2} is equal to *v*(*t*_{2})−*v*(*t*_{1}). (Here a common convention has been followed, in which the unit vector **i** in the positive direction along the line has been suppressed. The velocity and acceleration of the particle are in fact vector quantities equal to *v*(*t*)**i** and *a*(*t*)**i**, respectively.)

*Subjects:*
Mathematics.