Acceleration

When you are in motion, you are constantly adjusting your velocity and direction to match what is happening around you.

Changing velocity is called acceleration For example, when a bus starts from a rest,

its velocity increases. The bus accelerates.

Acceleration describes all situations in which velocity is increasing and decreasing

If acceleration does not change throughout it is called constant or uniform acceleration

The units for acceleration are the untis of velocity divided by the units for time

For example if a bus accelerates at +5m/s every second this is written as:

Other units can also be used, as long as they are a velocity to time comparison. For example, car advertisements sometime claim “0-100 in 5 seconds.”

What this means is that the car can accelerate from 0km/h to 100km/h in 5 s an acceleration of:

On average, at the end of each second the car is moving 20km faster than at the end of the previous second.

Astronauts are launched in a horizontal position because in that position the human body can briefly tolerate accelerations as great as 120m/s2. In the vertical position, acceleration of only 30m/s2 usually results in unconsciousness

Interesting fact:

Myriam Bedard accelerates on her skis from 6m/s [forward] to 15m/s [forward], a change of 9m/s[forward] in 1.5s. What is her acceleration during this time?

A skateboarder rolls down a hill with an average acceleration of +0.40m/s2. He is on the hiss for 4.8s. What is his change in velocity?

Acceleration while slowing down would be shown using negative signs as it is negative acceleration or deceleration. The calculation process is the same only with negative signs

In a race, a car travelling at 53m/s pr 190km/h comes in for a pit stop and comes to a full stop in 5.0s. What is the deceleration?