Student Exploration: 2D Collisions
Vocabulary: center of mass, conservation of energy, conservation of momentum, elasticity,
kinetic energy, momentum, speed, vector, velocity
Prior Knowledge Questions (Do these BEFORE
...
Student Exploration: 2D Collisions
Vocabulary: center of mass, conservation of energy, conservation of momentum, elasticity,
kinetic energy, momentum, speed, vector, velocity
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
1. A pool cue hits the white cue ball, which travels across
the table and strikes the red ball, as shown at right. Draw
a solid line to show the path you would expect the red
ball to take.
2. Draw a dashed line to show how you think the white ball
will move after it has struck the red ball.
Gizmo Warm-up
Objects collide all the time, but often with very different
results. Sometimes colliding objects will stick together. Other
times, they will bounce off each other at an angle. What
determines how objects will behave in a collision? You can
use the 2D Collisions Gizmo™ to find out.
Note the arrows, or vectors, on each puck. Click Play ( ).
1. How does the direction and length of its vector relate to the motion of a puck? The direction
and length o the vector determines the velocity of the puck.
2. The velocity (speed and direction) of each puck is described by components in the i and j
directions. The symbol for velocity is v. (Vector quantities are shown in bold.)
A. Which component represents movement in the east-west direction? i component
B. Which component represents movement in the north-south direction? j component
3. The speed (v) of a puck is equal to the length of its velocity vector. To calculate the speed of
a puck with a velocity of ai + bj, use the Pythagorean theorem: v a2 b2
Set the velocity of the blue puck to 12.00i + 5.00j m/s. What is its speed? v = 13m/s
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