User Arthur - Physics Stack Exchange

36 votes

Why did we expect gravitational mass and inertial mass to be different?

answered Apr 14, 2021 at 7:57

26 votes

Why isn't an infinite, flat, nonexpanding universe filled with a uniform matter distribution a solution to Einstein's equation?

answered Sep 24, 2018 at 6:50

25 votes

How does 'Tear Here' work?

answered Jun 12, 2017 at 7:17

10 votes

What do we mean when we say the CMB has a temperature and how do we measure it?

answered Jun 13 at 6:55

8 votes

Why is force a vector?

answered Dec 4, 2017 at 15:21

7 votes

Is energy more fundamental than force?

answered Nov 10, 2019 at 23:40

7 votes

Why isn't energy conserved in this collision problem?

answered Nov 2, 2018 at 8:29

7 votes

Are the Christoffel symbols all zero in gravity-free space?

answered Oct 16, 2017 at 11:25

3 votes

Accepted

How do 3D glasses work?

answered Oct 18, 2013 at 13:52

3 votes

Accepted

What force counteracts friction when a block is pulled?

answered Jul 20, 2014 at 8:54

2 votes

Why does a helium balloon rise?

answered May 31, 2019 at 9:25

2 votes

When a car accelerates relative to earth, why can't we say earth accelerates relative to car?

answered Sep 8, 2021 at 9:49

2 votes

How does an electric field apply force to charged particles?

answered Oct 21, 2022 at 8:37

1 vote

Length contraction of a square moving along the diagonal

answered Oct 24, 2023 at 17:57

0 votes

Why does blowing a whistle in someone's ear damage it more than blowing directly in their ear? Won't the whistle reduce overall energy?

answered Mar 10, 2023 at 10:21

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15 Answers

Why did we expect gravitational mass and inertial mass to be different?

Why isn't an infinite, flat, nonexpanding universe filled with a uniform matter distribution a solution to Einstein's equation?

How does 'Tear Here' work?

What do we mean when we say the CMB has a temperature and how do we measure it?

Why is force a vector?

Is energy more fundamental than force?

Why isn't energy conserved in this collision problem?

Are the Christoffel symbols all zero in gravity-free space?

How do 3D glasses work?

What force counteracts friction when a block is pulled?

Why does a helium balloon rise?

When a car accelerates relative to earth, why can't we say earth accelerates relative to car?

How does an electric field apply force to charged particles?

Length contraction of a square moving along the diagonal

Why does blowing a whistle in someone's ear damage it more than blowing directly in their ear? Won't the whistle reduce overall energy?