Speed and AccelerationBy: Ryan Pedrigi

Resident Scientist/Mathematician

What is speed?

A way of describing “how fast” something is moving.

More technically, speed is the rate of change of an objects position with respect to time.

Calculation of Speed There are a couple of different ways to

calculate speed Average speed, S, is simply the change

in position, x, divided by the time, t, taken to travel that distance…

IF

IF

tt

xx

t

xS

Maximum Speed = 62 mph

Applications of Speed: British Thrust SSC

Max Speed = 763 MPH

Applications of Speed: Supersonic Flight Max Speed = 1650 MPH (Mach 2.2)

Applications of Speed: Sky Diver Terminal Velocity = 200 MPH

Sample Problem: Speed A runner runs a

400 meter race in a time of 50 seconds.What is her average speed?

s

mS

tt

xxS

IF

IF

050

0400

smS 8

What is Acceleration?

A way of describing how fast something is speeding up or slowing down.

More technically, acceleration is the rate of change of an objects speed with respect to time.

Calculation of Acceleration As with speed, there are a couple of

different ways to calculate acceleration Average acceleration, a, is simply the

time rate of change of speed, S,…

IF

IF

tt

SS

t

Sa

Applications of Acceleration: Lamborghini

Accel. = 15.38 MPH/sec = 22.56 ft/sec^2Engine: 6 liter, V12

Horsepower: 550 @ 7100 RPMMaximum Speed: 210 MPH0-60: 3.9 sec0-100: 8.8 secPrice: $275,000

Applications of Acceleration: Space Shuttle Accel. = 64.87 MPH/sec = 95.14

ft/sec^2Speed Attained: > 17,500 MPHTime to Low Orbit: 11 min.Time to Space: 45 min.

Sample Problem: Acceleration

A motorcycle turns the corner of a race track at 85 MPH and then speeds up to 150 MPH on the straightaway. Knowing that it took 5 seconds to change speed, what is the average acceleration?

sMPH

att

SSa

IF

IF

05

85150

sMPHa 13