{"id":208,"date":"2026-06-11T00:37:33","date_gmt":"2026-06-11T00:37:33","guid":{"rendered":"https:\/\/physicsfundamentalsinfo.com\/blog\/?p=208"},"modified":"2026-06-11T00:37:35","modified_gmt":"2026-06-11T00:37:35","slug":"acceleration-in-physics","status":"publish","type":"post","link":"https:\/\/physicsfundamentalsinfo.com\/blog\/kinematics\/acceleration-in-physics\/","title":{"rendered":"What Is Acceleration in Physics?"},"content":{"rendered":"\n
Definition<\/div>

\nAcceleration in physics is the rate at which an object’s velocity changes with time. It is calculated as a = \u0394v\/\u0394t \u2014 the change in velocity divided by the time taken \u2014 and measured in metres per second squared (m\/s\u00b2). Because velocity includes direction, speeding up, slowing down and turning all count as acceleration.\n<\/p><\/div>\n\n

Feel that push into your seat as a plane begins its take-off run? That is acceleration making itself felt \u2014 your velocity is climbing by several metres per second, every second, and your body registers every one of them.<\/p>\n\n

A speedometer tells you how fast you are going. Acceleration tells you how quickly “how fast” is changing \u2014 and once that one idea clicks, half of mechanics falls into place.<\/p>\n\n

What Is Acceleration in Physics?<\/h2>\n\n

Hold the idea this way: speed describes how quickly your position<\/em> changes; acceleration describes how quickly your velocity<\/em> changes. A cruising airliner doing 900 km\/h in a straight line has zero acceleration. A sprinter exploding off the blocks \u2014 moving far slower \u2014 has plenty.<\/p>\n\n

Formally, acceleration is the rate of change of velocity<\/a> with time. It is a vector: it has a size and a direction, and both matter.<\/p>\n\n

Average vs instantaneous acceleration<\/h3>\n\n

Average acceleration takes the total change in velocity and divides it by the total time \u2014 ideal for whole journeys. Instantaneous acceleration is the value at one exact moment, found by shrinking that time interval until it is vanishingly small.<\/p>\n\n

If you go on to calculus, you will meet the instantaneous version as a = dv\/dt, the derivative of velocity with respect to time. In a first physics course, the average form does almost all of the work.<\/p>\n\n

The Acceleration Formula (and What m\/s\u00b2 Means)<\/h2>\n\n

Everything starts from one definition. Memorise this and you can rebuild the rest.<\/p>\n\n

a = \u0394v \/ \u0394t = (v \u2212 u) \/ t<\/div>\n\n
\n\n\n\n
Symbol<\/th>Meaning<\/th>SI unit<\/th><\/tr>\n<\/thead>\n
a<\/strong><\/td>acceleration<\/td>metres per second squared (m\/s\u00b2)<\/td><\/tr>\n
\u0394v<\/strong><\/td>change in velocity (v \u2212 u)<\/td>metres per second (m\/s)<\/td><\/tr>\n
u<\/strong><\/td>initial velocity<\/td>m\/s<\/td><\/tr>\n
v<\/strong><\/td>final velocity<\/td>m\/s<\/td><\/tr>\n
t<\/strong> (\u0394t)<\/td>time taken for the change<\/td>seconds (s)<\/td><\/tr>\n
s<\/strong><\/td>displacement (used below)<\/td>metres (m)<\/td><\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n\n

So what does m\/s\u00b2 actually mean? Read it as “(metres per second) per second”: an acceleration of 3 m\/s\u00b2 adds 3 m\/s of velocity during every second that passes. One second in, you have gained 3 m\/s; two seconds in, 6 m\/s.<\/p>\n\n

The constant-acceleration toolkit<\/h3>\n\n

Rearrange the definition and you get the most-used equation in kinematics \u2014 final velocity from initial velocity, acceleration and time:<\/p>\n\n

v = u + at<\/div>\n\n

And when you know the distance but not the time, this companion equation \u2014 valid only while acceleration is constant \u2014 closes the gap:<\/p>\n\n

v\u00b2 = u\u00b2 + 2as<\/div>\n\n