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47 views

### Convert inertia formula to excel calculator

I've been looking at this question: "Weight" of moving object in a car collision but to be honest I can't get my head around how to work it out myself (I'm not a physics student!). What ...
86 views

### How and why does momentum get transferred? [closed]

Let us imagine an isolated system and there are two objects of whatever masses and size. Let one object move towards the other object with constant velocity. We know, that when they collide, the ...
161 views

### Why equation $F = m a$ is not valid in relativistic physics but $F = dp / dt$ is valid?

I read that the equation $$F = m a$$ is not valid in relativistic physics. Instead $$F = \frac{d }{dt} \frac{mv}{ \sqrt{1- \frac{v^2}{c^2} } }$$ is valid in relativistic physics but why is that?
69 views

### How is force related to launching objects with a lever?

Suppose we have a class 1 lever, lifting a load of constant mass. All distances remain the same and the only thing that changes is the magnitude of the force applied (effort). Intuitively we know that ...
74 views

### What does the force acting on an object do to that object's motion

This was an exam question. The question simply states "What does a force acting on an object do to that object's motion?" The answer is A force changes an object's momentum. I thought the answer was ...
687 views

### Show that the initial speed of the block and the bullet, after they began to move off together, was 1.3 m/s

A bullet of mass 2.0g is fired horizontally into a block of wood of mass 600g. The block is suspended from strings so that it is free to move in a vertical plane. The bullet buries itself in the block....
84 views

### Can rapid acceleration have its own “version” of momentum?

I'm a high school student and I've only taken AP Physics one. Objects have momentum which is determined by their mass and velocity, but I'm wondering if there is something which continues increasing ...
96 views

### Determining the mass of my car via m = F/a

I'd like to do something unconventional. I'd like to weigh my car by hitting the gas. I have an accelerometer in my phone (a). I'm trying to determine the force the car is exerting (against the road, ...
141 views

### ${\bf F}=m{\bf a}$ versus ${\bf F}=\frac{\mathrm d{\bf p}}{\mathrm dt}$ alternate expressions (differential)

I am currently collecting research about theories to do with accelerated motion, and scientists who were involved in the development of such theories. Intrinsically, Newton's Second Law came up. ...
325 views

### Fundamental principle of Dynamics - Newton

Since my early studies, I have learned the principle of Newton for the law of dynamics as follows: $$\sum \vec{F} = m \vec{a}\tag{1}$$ with $\sum \vec{F}$ all the forces applied on the object, $m$ ...
147 views

### What is 3-Force and 3-acceleration?

I can't seem to find any information related to the 3-Force or the 3-acceleration, only for the 4-force and 4-acceleration. Could someone explain the difference? The context is that I'm trying to ...
386 views

### Momentum with Constant Acceleration

Can someone correct my understanding on this? So, if an object has constant acceleration, and travels a distance $x$, it means its momentum will change by $mv_2 - mv_1$. Now, if the same object ...
184 views

### Can objects accelerate due to their own gravity?

Gravity is at least primarily based on mass, more mass = more gravity. Planets and stars are spherical because gravity is great enough to compress them into spherical shapes, but (at least as I ...
170 views

### According to Newtonian mechanics, can there be an acceleration while no force is acting on a body with mass? [closed]

Consider a body of mass $m$ moving in space and not interacting with anything else. The body is moving at a constant velocity and now it starts shedding off its parts. Eventually its mass will ...
29 views

### Single atom thruster

Would it be possible to accelerate a single atom inside a space ship that, after exiting the ship's exhaust, it would take the ship from Earth orbit to Mars?
173 views

### If photons have no acceleration, how can they have energy and momentum? [duplicate]

The change in speed of a photon with respect to time is 0 as photons travel at $c$ forever. If no change in speed exists, how can photons have momentum and acceleration? I guess they don't work like ...
326 views

### Collision/Crumpling problem possible solution mistake

This question is from Physics for scientist and engineers , Ohanian . Two automobiles of 540 and 1400 kg collide head-on while moving at 80 kmh in opposite directions. After the collision the ...
558 views

### Why is the acceleration of the center of mass is equal to 0 in this problem?

I don't understand why the center of mass' acceleration is equal to 0 when the center of mass should be moving as an external force is exerted on the cue ? Billiard Balls. Now we can go back and ...
55 views

### What is the minimal G-force curve in 2-dimensional space?

Given two parallel roads, which need to be connected, what shape of curve would produce the minimum overall horizontal G-force(s) on travelers? Is it a $sin$ or $cos$ wave? Is it a basic cubic ...
483 views

### How to compensate a top-heavy platform [closed]

I have a small four-wheeled platform weighing 1.3kg with a height of 30cm. Its center-of-mass is located at 75% of the height, making it a little top-heavy. I empirically measured the angle at which ...
110 views

### Analogy Between Momentum and Faraday's Law of Induction

What is the reason behind momentum, during acceleration? Mass resist velocity change during acceleration similar to Coiled wire resisting Current amount change. The similarity is worth looking at. ...
966 views

### How does constant thrust avoid quadratic kinetic energy accumulation?

I haven't found the right search terms for this question, so if it has been answered, references would be welcome. Suppose we start from experimental station in deep space (interstellar space if need ...
49 views

### Will the flash light accelerate in space? [duplicate]

As we know from school physics course light has pressure. So my question is will flash light accelerate in space in the direction opposite to light emission? If not, then will flash light with ...
1k views

### The acceleration of the centre of mass [closed]

Given two balls that are thrown straight up in the air at a speed of $40 \:\mathrm{m/s}$, $0.10 \:\mathrm{s}$ apart. One ball is twice the mass of the other. The heavier ball is thrown second. I'm ...
3k views

### Force of an object “skidding”?

Let's say I put the brakes on really suddenly in a car that was moving at 40mph. If I know how much force it takes to break the adhesion of the wheels, how do I find the force the car is exerting? ...
114 views

### Why can we model a body to have a center of mass?

I accept that bodies have a center of mass. I also accept that if I were to suspend a body by only supporting it at its center of mass, then the body wouldn't rotate. In the scenario that we suspend a ...
404 views

### What matters more in the strength tester game at a carnival, momentum or force?

A buddy and I were arguing over which matters more in the strength tester game (assuming the same accuracy of the hit): 1) momentum or 2) force. He was arguing that if you swing the hammer directly ...
184 views

### Can acceleration be achieved without reaction mass?

In a previous question, I asked whether a flashlight can accelerate me. The answer is yes. This has led me to wonder, this is inferior to all other known propulsion methods in all aspects except one: ...
10k views

### Deriving $F = ma$ - Newton's Second Law of Motion

Context: In my textbook it is given: 'momentum' short for 'linear momentum': Mass = $m$, momentum is $p=mv$. In time $\Delta t$, momentum changes by $\Delta p$, the rate of change of momentum is: ...
306 views

### Movement in outer space via Newton's law of every action has an equal and opposite reaction

What is more effective for travel in outer space ignoring all other factors like air radiation etc. I have a 10 kg bag of rice would I travel faster throwing the whole bag at once or throwing a grain ...
3k views

### Punching - Force or Momentum?

If I want to punch a person inflicting maximum damage, what do I need to care about? My force of punching, i.e, do I need more acceleration? Or do I need momentum, i.e my velocity for punching?
42k views

### Calculating force of impact

Since $\text{force = mass}\times\text{acceleration}$, is it right to say that an object traveling at a high constant velocity (zero acceleration), exerts zero force upon impact with a stationary ...
69k views

### Small car colliding with large truck

A small car collides with a large truck. Why do both vehicles experience the same magnitude of force? Wouldn't the large vehicle experience less force than the small one?