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-1 votes
2 answers
92 views

Infinitesimals meaning in this context

I was solving this rocket propulsion's classic mechanics exercise: M is the instantaneous rocket's mass, and v its velocity. The exhaust gases are ejected with speed 𝑢 relative to the speed 𝑣 of the ...
arpg's user avatar
  • 169
-2 votes
1 answer
154 views

What is wrong with my approach? What error did I make mathematically? [closed]

A $4$ kg object is moving in one dimension along the x-axis. The linear momentum of the object increases with the position of the object according to the following equation: $p(x)=6+3x$ At $t = 0$ s ...
bfff's user avatar
  • 1
0 votes
1 answer
1k views

How to use Newton's second law to derive conservation of momentum and how to use derive conservation of momentum to derive the second law?

I know if taking the integral of $F=ma$, then I can get $p=mv$. I'm weak in calculus, so I wondered how to do this exactly. Is there anything wrong in my logic below? \begin{align}\int F\left(t\...
ZJj's user avatar
  • 1
0 votes
1 answer
182 views

Linear Momentum/Impulse for a Rigid Body

Problem Consider a system of $N$ point-masses $m_i$, each travelling at a velocity $\mathbf{v}_i$. Then, the total linear momentum / impulse $\mathbf{p}$ of the system can be calculated as (see Smith,...
Discbrake's user avatar
  • 105
1 vote
3 answers
169 views

Integral ambiguity

I'm a bit confused with some notation I encounter in physics calculus. Consider this: Taken from here. Integration operates on functions, correct? What does it mean to integrate $\frac{d{\bf p}}{dt} ...
RustyDoorknobs's user avatar