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Title: CONSTANT SPEED

Purpose
Measure distance and time of moving object, and graphically analyze its motion.

Concept
In order to know how something moves, we have to know where it is. Knowing where it is usually requires choosing a reference point - a place to compare to. In physics, we usually use the ground, a tabletop or the floor as a frame of reference. The ratio of the distance covered to the time required is called speed. When the direction of the motion is included with speed we have what is known as velocity.

Materials

Procedure
1. Take a stopwatch and a meter stick to a running track.
2. Use the meter stick to measure 50 m, and mark the distance every 10 m with pieces of masking tape.
3. Measure the time it takes to walk, at a constant pace, from 0 to 50 m. Record the elapsed time for each 10 m interval.
4. Measure the time takes to jog, at a constant pace, from 0 to 50 m. Record the elapsed time for each 10 m interval.

Observations and Data:

Walking:
 Time (s) Displacement (m) 0.0 0.0 10.0 20.0 30.0 40.0 50.0

Jogging:
 Time (s) Displacement (m) 0.0 0.0 10.0 20.0 30.0 40.0 50.0

Make a graph of displacement (vertical) versus time (horizontal) for walking and jogging.

Analysis
1. Find the slope of the walking and jogging graphs. What does the slope of the graph mean?
2. From your graph, determine how long it took to walk the first 25 meters.
3. Predict how long it would take to walk 400 m.

Application
Driving a car at 90 km/hr, how many hours would it take to travel 360 km?