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Velocity and

Acceleration

Velocity

Change in velocity can be due to:

Change in speed

Change in direction

Velocity

If a man walks 25 km east for 14

min, what is the velocity of the

man?

Unknown and Knowns Formula Plug In #’s Answer with Unit(s)

s =

d =

t =

Velocity Can Be Combined

10 m/s East 5 m/s East

10 m/s East 5 m/s West

• If both velocities are in the same

direction, then add them.

• If both velocities are in opposite

directions, then subtract them.

= 15 m/s East

= 5 m/s East

Combining Velocities If a boat is going 25 km/h south

down a river which is flowing at a

velocity of 10 km/h south, what

would be the actual velocity of

the boat? (draw arrows)

Velocity = 35 km/h south

Combining Velocities

If you are rowing a boat 16 km/h

east on a river with a velocity of

6 km/h west, what would your

actual velocity be? (draw arrows)

Velocity = 10 km/h east

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Acceleration

Change in velocity

Could be a change in speed

and/or a change in direction

Acceleration

Vf = Final speed (ending speed)

Vi = Initial speed (starting speed)

t = Time

a = Acceleration

Units: velocity/time Ex: m/s2

a = vf - vi

t

Acceleration

A car’s speed changes from 35 m/s

to 70 m/s in 6.0 s. What is the

acceleration of the car?

Acceleration = 5.8 m/s2

Acceleration A parachute on a drag-racer opens and

slows the car down from 70 m/s to 30

m/s in 5.0 s. What is the acceleration

of the car?

Acceleration = - 8 m/s2

(negative # indicates deceleration)

Acceleration Graph

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