Definition: rate of change of velocity
Standard Units: meters per second per second (m/s ## Average AccelerationAcceleration is the change in velocity per time interval. Note that this formula leads to units of m/s2 because velocity is m/s and time is s. This formula can be rearranged, with some changes to the symbols, to give
Because velocity is a vector, acceleration is also a vector. If a velocity vector changes direction, then it is a different vector and so D **A change in (vector) direction is also an acceleration**
So even turning counts as acceleration. Thus the steering wheel in your car is also a kind of accelerator. If you think about it, this makes sense because you **Zero acceleration means traveling at constant speed in a straight line.**
## Units for accelerationThe standard SI units for acceleration is a meter per second per second, meaning an acceleration that increases the velocity by one meter/second every second. This is usually express as one m/s A An F-16 fighter can take a 9- Human tolerance depends on both the acceleration and the length of time the acceleration is endured. People can tolerate 45g for 0.1 seconds or 10 g for 1 second. In a car crash with seat belts, the acceleration is about 100g for 0.03 seconds, which is survivable, but an acceleration of 100g for 0.10 seconds would be fatal (the aorta ruptures from the pressure buildup). ## Graphical Interpretations
Suppose a mass is starting from rest ( - Calculate the new velocity from
*v*_{new}=*v*_{old}+*at*, with*t*= 1 second. - Calculate the new position from
*x*_{new}=*x*_{old}+*t*, using = average velocity of current and previous interval.
We have to use the average velocity to calculate the new distance, because the velocity is not a constant (it is accelerating).
## Acceleration ExampleZero to 60 mph in 3 seconds, expressed in “ |