Top 5 Physics Riddles: How to Solve and Understand Them with Expert Tips"

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The discussion revolves around solving five physics riddles related to forces and motion. Key points include understanding that pushing a crate at constant velocity indicates that friction matches the pushing force, and that objects can move with zero net force due to inertia. The weight read on a scale reflects the support force acting on a person, while equal and opposite forces result in a net force of zero. Additionally, the tension in a rope holding a stationary object equals the weight of that object. Overall, the riddles emphasize concepts from Newton's laws, particularly the relationship between forces and motion.
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i have 5 ridles my teacher posts and i was wonder if somebody could help me and put in some adivce/tips.

1. If we push a crate at constant velocity, how do we know how much friction acts on the crate compare to our pushing force?

2. Give an example of something moving when a net force of zero acts on it.

3. When you weigh yourself, are you actually reading the support force acting on you, or are you really reading your weight?

4. When only a pair of equal and opposite forces act on an object, what is the net force acting on it?

5. How much tension is there in a rope that holds a 20-N bag or apples at rest?

go nuts guys!
 
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1, 2, and 4 are the same.

Time for you to go nuts.
 
Hints: c.f.

1. Newton I
2. see above Q for perfectly fine example, why?
3. Newton III
4. Vectors
 
Chi Meson said:
1, 2, and 4 are the same.

In fact, all of them except #3 are about the same idea. What is true about an object when the net force on it is zero?

As for #3, consider the forces that act on the scale platform when you stand on it.

As for getting your questions or puzzles answered around here, you're supposed to share your own thoughts first before anyone will give you more guidance...
 
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