Phy40-Lesson 4
Velocity in the Position-Time graph
1. Differentiate between speed and velocity.
2. Represent mathematically, the average velocity as
3. Interpret the slope of a position-time graph as the average velocity and the absolute value as the average speed
4. Explain how average velocity is different from instantaneous velocity
5. Explain the meaning of the slope of a position-time graph that is upward or downward and above or below the x-axis.
6. Interpret the position of an object after a time interval by using;
Differentiate between speed and velocity.
Average Velocity of an object is its displacement divided by the corresponding time interval
The SI unit of velocity is m/s
Velocity is a vector quantity.
Speed on the other hand is defined as the distance covered divided by the corresponding time interval
Speed is also measured in m/s
Speed is a scalar quantity.
1. If Steve throws the football 50 meters in 3 seconds, what is the average speed of the football?
2. If it takes Ashley 3 seconds to run from the batters box to first base at an average speed of 6.5 meters per second, what is the distance she covers in that time?
3. Bart ran 5000 meters from the cops and an average speed of 6 meters/second before he got caught. How long did he run?
find the position cf = nt+ ci
POSITION The figure shows a motorcyclist traveling east along a straight road. After passing point B, the cyclist continues to travel at an average velocity of 12 m/s east and arrives at point C 3.0 s later. What is the position of point C?
Interpret the slope of a position-time graph as the average velocity and the absolute value as the average speed
AVERAGE VELOCCITY The graph at the right describes the straight-line motion of a student riding her skateboard along a smooth, pedestrian-free sidewalk. What is her average velocity? What is her average speed?
Explain the meaning of the slope of a position-time graph that is upward or downward and above or below the x-axis.
Calculate the average velocity between [0s and 5s], [5s and 10s], [10s and 15s]
Describe the motion of A, B, C, D, and E
A : At Rest
B: negative velocity
C: At Rest
D: Positive velocity
E: At Rest
When is the object at rest?
between 5s and 10s
When is the object moving in the positive direction? at what speed?
between 0s and 5s
At what time interval does the object move fastest?
10s to 12.5s because the live is the steepest
Explain how average velocity is different from instantaneous velocity
Constant Velocity
Positive Velocity
Positive Velocity
Changing Velocity (acceleration)
Average velocity
Is calculated For a time interual
Instanteneous velocity
Is the velocity at a ceitain time