Skip to main content
Physics

Return to Question

Post Closed as "Duplicate" by Sandejo, Jon Custer, jng224, GiorgioP-DoomsdayClockIsAt-90, ZeroTheHero
added 38 characters in body
Source Link
Acephalus
Acephalus
  • 189
  • 6

What is the conceptually difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|$$$$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|\equiv \bigg|\frac{d\vec{r}}{dt}\bigg|$$ Unidimensionally it appears an equality, but Im having trouble to think qualitatively.

What is the conceptually difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|$$ Unidimensionally it appears an equality, but Im having trouble to think qualitatively.

What is the conceptually difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|\equiv \bigg|\frac{d\vec{r}}{dt}\bigg|$$ Unidimensionally it appears an equality, but Im having trouble to think qualitatively.

added 2 characters in body; edited tags; edited title
Source Link
Qmechanic ♦
Qmechanic ♦
  • 213.1k
  • 48
  • 590
  • 2.3k

simple Simple difference between module of velocity and time derivative of module of position

What is the conceptualyconceptually difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|$$ UnidimensionalyUnidimensionally it appears an equality, but Im having trouble to think qualitatively.

simple difference between module of velocity and time derivative of module of position

What is the conceptualy difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|$$ Unidimensionaly it appears an equality, but Im having trouble to think qualitatively.

Simple difference between module of velocity and time derivative of module of position

What is the conceptually difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|$$ Unidimensionally it appears an equality, but Im having trouble to think qualitatively.

Source Link
Acephalus
Acephalus
  • 189
  • 6

simple difference between module of velocity and time derivative of module of position

What is the conceptualy difference between the two: $$\frac{d|\vec{r}|}{dt}=\frac{\vec{r}\cdot\frac{d\vec{r}}{dt}}{|\vec{r}|}\neq|\dot{\vec{r}}|$$ Unidimensionaly it appears an equality, but Im having trouble to think qualitatively.