Acceleration lab• Goals: –What does a distance vs. time graph look like

for an accelerating object?–How do we find the instantaneous velocity of

an object using a distance vs. time graph.

Background• Define all variables used in the lab and write-up.– Include formula symbols and units• Time, distance, instantaneous velocity, acceleration.

• Explain how a tickertape timer works• Explain what constant speed looks like according to

a particle diagram of motion.(draw example)

• On a distance vs time graph, explain what constant speed would look like (sketch an example)

Predictions

1. Will the falling weight be moving at constant speed or accelerating?

2. Based on this answer, what do you predict the tickertape will look like?- Draw it!

3. What will the distance vs. time graph of the falling weight look like?- Sketch the ‘shape’ of it

Lab Setup

Text book

500g mass

Ticker tape

Ticker tape timer

Ring Stand

MaterialsRing stand, mass, old text book, tickertape, tickertape timer, meter stick.

Procedure• Set up your apparatus.• Rip off a piece of tickertape that is as long as the

distance from the floor to the top of the ring stand.• Feed a piece of ticker tape UNDER the carbon circle.• Tape that end to the top of the mass• Turn on the tickertape timer• Drop the mass onto the book. (the tickertape

should feed through the timer)• Turn off the timer.• Measure the distance from the start to every

______ dot.

DataDistance vs. Time

Total Distance (m) Elapsed Time (s)

GraphDistance vs. Time

Time (s)

Dist

ance

(m)

Finding Instantaneous Velocity

Time (s)

Dist

ance

(m)

1. Pick a point ON your curve that is well defined.

2. Use a RULER to draw a line TANGENT to your graph at that point.

3. Pick a second point on your tangent line

POINT ONLINE

POINT OFFLINE

Slope Calculations

onlineoffline

onlineoffline

xx

yy

x

yslope

DataInstantaneous velocity vs. Time

Time (s)X-coordinate ON the

curve

Instantaneous Velocity (m/s)

Slope of the tangent line

Finding Acceleration

Time (s)

Inst

anta

neou

s Ve

loci

ty(m

/s)

x

yslope

conclusion• Was your object at constant speed or accelerating.• Sketch your tickertape. Did it match your

prediction?• Sketch your d vs t graph, did it match your

prediction?• Describe how you get instantaneous velocity on a

distance vs time graph• What quantity does the slope of a velocity vs time

graph represent (check the units)• Offer at least 2 sources of error• What is a future experiment that you could do?