Questions tagged [collision]
This tag is for questions relating to collision which is the interaction between two or more bodies that results in physical contact and an exchange of momentum between the bodies involved. When it happens, kinetic energy is often exchanged between the molecules’ translational motion and their internal degrees of freedom.
1,944
questions
205
votes
4
answers
85k
views
Why doesn't matter pass through other matter if atoms are 99.999% empty space?
The ghostly passage of one body through another is obviously out of the question if the continuum assumption were valid, but we know that at the micro, nano, pico levels (and beyond) this is not even ...
- 3,936
91
votes
7
answers
26k
views
Why does a billiard ball stop when it hits another billiard ball head on?
(I'm repeating myself a lot here, but it's because I want to make my confusion clear.)
If 2 billiard balls are the same exact mass, and one hits another stationary one head on, I have heard that the ...
- 3,075
78
votes
14
answers
21k
views
Does throwing a penny at a train stop the train?
If I stand in front of a train and throw a penny at it, the penny will bounce back at me.
For the penny to reverse its direction, at some point its velocity must go to zero. This is the point it hits ...
- 767
69
votes
6
answers
13k
views
Why does a ping pong ball bounce higher when it is dropped together with a cup of water?
Setup: an official ping pong ball is floating inside a party plastic cup filled with clean water, which is then dropped from a certain height onto a soft mat.
Observation: the ping pong ball shoots up ...
- 13k
63
votes
17
answers
217k
views
How can momentum but not energy be conserved in an inelastic collision?
In inelastic collisions, kinetic energy changes, so the velocities of the objects also change.
So how is momentum conserved in inelastic collisions?
- 633
53
votes
3
answers
10k
views
Why does the speed of a ping pong ball increase when the space in which it can bounce decreases?
I was playing table tennis the other day when I my ball fell off the table. I placed my paddle above it in order to slow it down, and then I brought the paddle to the ground so that the ball would ...
- 701
51
votes
4
answers
17k
views
Can a tomato pierce a hole in a steel plate if only the tomato is travelling fast enough?
A tomato is travelling very fast towards a 1 cm thick steel plate.
Let's say this happened in a vacuum, so that the air resistance wouldn't rip the tomato apart before it even hit the steel plate.
...
- 656
50
votes
6
answers
20k
views
Why don't all objects bounce like rubber balls?
Some things don't bounce like rubber balls do. For example, books don't bounce much when dropped.
Why is it that some things bounce while others don't?
- 617
45
votes
4
answers
15k
views
What would happen if Jupiter collided with the Sun?
This question is inspired by a similar one asked on Quora. Let's say a wizard magicked Jupiter into the Sun, with or without high velocity. What happens?
The Quora question has two completely opposed ...
- 21.4k
44
votes
6
answers
16k
views
For collision, physical contact is not a necessary condition. Why?
In my textbook, it is written that
"For collision, physical contact is not a necessary condition".
How can collision occur without physical contact? If there is no physical contact, then there ...
- 646
44
votes
6
answers
27k
views
Newton's 3rd law... hitting drywall (which I break) vs hitting a brick (which breaks me)?
According to the Third Newton's law of motion:
For every action there is an equal and opposite reaction.
So, I understand that if I hit a brick wall with $50\, \mathrm{lbs}$ of force, the brick ...
- 1,066
40
votes
6
answers
28k
views
Newton's cradle
Why, when one releases 2 balls in Newton's cradle, two balls on the opposite side bounce out at approximately the same speed as the 1st pair, rather than one ball at higher speed, or 3 balls at lower ...
- 401
39
votes
1
answer
6k
views
Why don't merging black holes disprove the no-hair theorem?
The no-hair theorem of black holes says they're completely categorised by their charge and angular momentum and mass.
But imagine two black holes colliding. At some point their event horizons would ...
user84158
38
votes
13
answers
13k
views
If water is nearly as incompressible as ground, why don't divers get injured when they plunge into it?
I have read that water (or any other liquid) cannot be compressed like gases and it is nearly as elastic as solid. So why isn’t the impact of diving into water equivalent to that of diving on hard ...
- 515
36
votes
4
answers
8k
views
What would happen if an accelerated particle collided with a person?
What would happen if an accelerated particle (like they create in the LHC) hit a person standing in its path?
Would the person die? Would the particle rip a hole? Would the particle leave such a tiny ...
user60228