v = velocity (m/s)

t = time (s)

Δs = distance travelled (m)

### Mechanics index

next: accelerated motion>>

Mass and weight

Uniform movement

Accelerated movement

Work / energy

Kinetic energy

Power

Momentum

Collisions

Force

Pressure and force

Elastic force (Hooke's Law)

Projectile motion

## Uniform motion: constant velocity

This is the simplest kind of motion.

It only depends on time and velocity.

Examples

1) If you travel from Brighton to London (50 miles) in 1 hour, what is your (average) velocity?

v = 50 miles / 1 hour = 50 miles / hour

2) If I travel at 100 miles an hour for 3 hours, how far do I get?

Δs = 100 * 3 = 300 miles

Converting miles per hour into m / s :

We normally must work using SI untis, which in thi case are m and s.

It is then necessary to know how to convert from more usual speed units, like km/h or mph, to m/s. Here is how to do:

-Converting km/h (kilometers per hour) to m /s (meters per second):

we know that 1 km = 1000m and that 1 hour = 3600 s, so:

1 km / h = 1000 m / 3600 s = 0.28 m/s

so: 1 m/s = 3.6 km / h

-Converting mph (miles per hour) to m/s (meters per second):

1 mile/ h = 1600 m / 3600 s = 0.44 m / s

3) Convert 100 mph into m/s.

1 mph = 0.44 m/s

100 mph = 44 m/s