What do angles have to do with math?
If the cue ball does not hit the object ball full in the face, the object ball will start travelling at an angle instead of straight ahead along the aim line.
If you have not worked with angles before, your teacher will first refer you to this link for a quick instruction on angles.
Now back to the cue ball that does not hit the object ball full in the face.
Here is the reason why
The image below shows a front view of a half ball hit, with the diameter of the object ball overlapping the cue ball by half at the moment of contact. The centre of the cue ball is on the edge of the object ball.
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Hours of Work
July 2021
Construction Date
Task 1
What angle do you think the object ball will continue to travel in the event of a half ball
1. Exactly 45 degrees
2. More than 45 degrees
3. Less than 45 degrees
Tip: first draw a top view of the situation yourself, based on the front view!
In the top view here, it is clear that the object ball must be hit by less than half the thickness of the ball to start travelling under a 45-degree angle. Therefore, the angle will be smaller if contact is made fuller on in the face.
Task 2
The image on the right (and on the worksheet) shows a top view of the situation in which the cue ball is played in such a way that it hits exactly half the object ball.
It appears that the angle at which the object ball start travelling is 30 degrees.
There are several ways to argue that it actually does!
Use the worksheet to investigate why the object ball truly starts travelling at an angle of 30 degrees in this situation and write down your reasoning.
Stuck?
Ask your teacher for some hints!
