Five examples of acceleration

Answer 1

-- Start a car moving from a stop-sign.

-- Slow a car down when approaching a stop-sign.

-- Turn a corner in a car.

-- Turn a corner on a bicycle.

-- Turn a corner on roller-skates.

-- Throw a stone at a stop-sign.

-- Drop a stone into a pond.

-- Throw a stone horizontally half-way across a pond.

-- Throw a stone up to get it all the way across a pond.

-- The moon sailing around the Earth in its orbit.

-- Practically every motion of anything that you ever see during daily life on Earth.

We're in the category of here, so we need to be a bit careful about

how we handle scientific terms like this.

Contrary to popular usage, "acceleration" does notmean increasing speed, and

an object that's accelerating is not necessarily expected to be moving faster.

Acceleration means any change in speed ordirection of motion, and any object

that's not moving at a constant speed in a straight line is accelerating.

A car speeding up after leaving a stop-sign is accelerating, with positive acceleration

because its speed is growing. A car slowing down as it approaches an intersection

is accelerating, with negative acceleration because its speed is shrinking.

A car or bicycle on a curve, as well as the moon and any other object in a gravitational

orbit, is accelerating, because, although its speed may be constant, the direction

of its motion is changing.

And while we're being more precise than usual, velocityand speed are two

different things. Everybody knows what speed is. Velocity is speed and the

direction of the speed. If you drive around a curve at a steady 30 mph (48 kmph),

your velocity is changing, because, although your speed is constant, your direction

is changing.

And any change of velocity is called . . . . . acceleration.

Answer 2

A car braking to slow down. (deceleration)

An Olympic sprinter accelerating at an average of 3 m/s2. (acceleration)

A ball thrown up experiencing deceleration when going up and acceleration when going down.

Weight is dependent on one's mass and the standard gravity. (gravitational acceleration)

Swinging a ball around in a circle, which experiences center seeking force. (centripetal acceleration)

Answer 3

acceleration due to gravity