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4 votes

Significant figures when product is more by a factor of 10

The calculation of errors is important. With the limited information that is given one can make an estimate of the error in the area by assuming the last digit in a length is in error by $\pm 1$. ...
Farcher's user avatar
  • 97.9k
3 votes

Is gravitational potential energy of body by $mgh$ negative?

The two expressions have different locations for their energy zero points, that is why they disagree. $mgh$ is zero at wherever you have set $h=0$ to be with your coordinate system. Typically that is &...
Marius Ladegård Meyer's user avatar
3 votes

How Can there be a Gravitational Potential when there is NO Gravitational Field?

You would be right, if you took your reference, at the center of the sphere, to be at a potential of 0. Throughout the sphere, you have a constant potential, which would remain 0. Generally, we take $...
ekl1pse's user avatar
  • 31
2 votes
Accepted

Significant figures when product is more by a factor of 10

In the real world, measuring things perfectly isn't always possible. Those super precise numbers (like 208.74 cm²) are great for the calculator, but when it comes to the actual size of the plate, ...
Momo's user avatar
  • 36
1 vote

Is gravitational potential energy of body by $mgh$ negative?

The key here is that it is the difference in potential energy that is important and this yields the same result in magnitude and sign, using using either equation. The potential energy is obtained by ...
KDP's user avatar
  • 6,217
1 vote

What's the difference? $\nabla_\mu e_\nu=\Gamma_{\mu \nu}^\rho e_\rho~\text{ and }~\partial_\mu e_\nu=\Gamma_{\mu \nu}^\rho e_\rho~?$

The expression $\partial_\mu \mathbf{e}_\nu$, at face value, does not really make sense in curved space due to the vectors being in different tangent spaces. In order to make it work, vectors need to ...
Vincent Thacker's user avatar
1 vote

Why is work done by force $+mgh$ in the situation of throwing something up?

You are right, the work applied is not necessarily equal to $mgh$. To see this, let's look at energy conservation: $$K_0+U_0+W_{\text{n.c.}}=K_f+U_f$$ where $K_0$ and $K_f$ are the initial and final ...
BioPhysicist's user avatar
  • 57.2k

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