I have questions about acceleration and velocity?

Question

How can I solve problems like this?

A car accelerates from rest at -3.00 m/s2.

a. What is the velocity at the end of 5.0 s?
b. What is the displacement after 5.0 s?

How can I work this kind of problem? What do I need to remember for solving problems that inlcudes acceleration and velocity? If any1 help, help will be really appreciated.

Answer 1

See the reference web page. The basic equations, sometimes referred to as SUVAT, relate S (distance, or as it is often called, X), U (initial velocity, also Vi or V0), V (final velocity, also Vf or V1), A (acceleration) and T (time of applied acceleration). Acceleration is assumed constant for these equations, and many exercise problems and practical engineering approximations assume that. (For nonconstant acceleration you generally have to resort to calculus or time-stepped simulation.) Now the answers:
a. v = at = -3*5 = -15 m/s (in reverse, yet! Pretty daring.)
b. s = at^2/2 = -3*5^2/2 = -37.5 m