Questions tagged [newtonian-mechanics]

Newtonian mechanics covers the discussion of the movement of classical bodies under the influence of forces by making use of Newton’s three laws. For more general concepts, use [classical-mechanics]. For Newton’s description of gravity, use [newtonian-gravity].

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How to calculate the deflection angle of a pool ball based on distance, exit angle, and applied force?

I'm working on a pool game and would like to apply a somewhat realistic view, so i need to know how to calculate the angle that a pool ball returns after touching the edge of the table. the problem is ...
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Confusion on Normal force and its resolution on inclined plane

I had the following doubt regarding normal forces and its resolution on inclined plane. (Also I am quite new to SE, so I have no idea how do we upload diagrams to better represent my arguement). ...
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2answers
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Work done on an object whilst lifting it

Imagine to lift an object with mass $m$ from height $h_1$ to height $h_2$ and neglect the friction with air. How much work have you done on the object? My answers (big doubt in the second one!): ...
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Is Newton's 3rd law only valid when bodies are in contact?

All the examples explaining 3rd law in my textbook are instances when bodies are in contact, like when we walk for example; we press the ground with our feet, so the ground exerts an equal and ...
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Is there a mega structure that passively maintains a stable orbit around a star?

I've been thinking about mega structures. I am wondering whether there exist any mega structure that is passive and maintains a marginally stable trajectory around a star? By passive I mean that it is ...
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Can centrifugal force exist in non-Newtonian mechanics?

Judging on the fact that there are certain non-Newtonian fluids, that behave in a way adverse to Newtonian Mechanics, such as oobleck, is there a way for the idea of centrifugal force to exist outside ...
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Forces on object hung by two ropes

The rectangular object shown above is hung by two ropes at the points P and Q. As we can see, these points are far apart from each other(they are not the same point). So, How do I draw the resultant ...
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Circularity In Definition Of Force?

So my college physics book defines a force as a push/pull, but mainly a vector quantity, having both magnitude (strength) and direction. Yet it also defines the unit of a Newton, as THE FORCE, ...
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Pulley system with constraints

Now I need to find out the acceleration of pulley A. I know that (acceleration of a) = 2(acceleration of c) and the accelerations of A and C are in opposite directions using constraints. The solution ...
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1answer
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Decrease of the rotation speed of a wheel with inertia, when we stop applying rotational force to it [closed]

Let's say we have a wheel rotating at a constant speed $s$. Suddenly at time $t=1$ we stop applying force to it. What is the law for the decrease of the speed, until it stops? I guess it will look ...
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Calculate deceleration of a balls compression as it hits the floor, from air pressure and elasticity

A ball bounces for 2 reasons: A bouncy ball is made out of rubber, as that shape deforms and presses into the ground it restores itself to normal (because it elastic) and that converts the velocity ...
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Conservation of momentum using impulse equations

There is an inclined plane on a frictionless surface. A ball strikes the inclined plane horizontally with velocity $v_o$ and moves vertically after collision with velocity $v$ (see figure) mass of ...
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3answers
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Confusion about Newton's third law [closed]

The question: A toy rocket consists of a container of water and compressed air.Water is pushed vertically downwards through a nozzle by the compressed air. The rocket moves vertically upwards. The ...
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What does the phrase "block is sliding upwards" mean here?

So there was this question I came across. Now, there is the last line of the question that bothers me. As a result, the cube slides upwards and the block is moving with an acceleration a. What does ...
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1answer
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Can a whip be used to launch objects? [closed]

The inspiration of this question idea is: Balearic slingers could potentially have the effectiveness as a bullet and have a range of 400m (https://www.youtube.com/watch?v=3uDtrwNY0Zk&t=290s) the ...
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Final position of weight hanging from two opposed pulleys on ropes

Let's say I have the situation pictured below. The red and green ropes are tied to immobile supports. The ends of the red and green ropes are attached to frictionless rings. The blue rope is tethered ...
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How do we know that forces "add" like vectors?

As we all know the basic principle of vector addition. construct a parallelogram as shown, and the diagonal would be the resultant vector. As a mathematical method or formula, it is perfect to define ...
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Does rotational kinetic energy convert to translational energy when an spinning/revolving object is released in space/vacuum/air(no resistance)?

If an object (symmetric and circular/cylindrical/spherical) is made to roll on a surface and is made to fall from the edge of the surface, will its rotational kinetic energy convert to translational ...
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Forces on us on a rotating Earth

So the earth is constantly rotating but it doesn't need a force to rotate. It'll rotate indefinitely.(?) But we and other masses on earth need a force on us to continue rotating along with earth? And ...
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What is a negative force actually?

If we find the force for a decelerating object (let's say a car on a road), we'll see that the force is negative as in it’s in the opposite direction of the motion of the object. I wanna know what ...
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1answer
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Conservation of Momentum - Rocket

I was wondering why the mass of the fuel is regarded as -dm and the mass of the rocket as m+dm? I understand that the total mass has to be unchanged (ie m). Why can't I say that the rocket's mass is m-...
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Which component of velocity should we choose? [duplicate]

In the arrangement shown in the figure, the ends P and Q of an inextensible string move downwards with uniform speed u. Pulleys A and B are fixed. What is the speed with which mass m moves upward? The ...
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What will be the reading of spring balance in the following situation?

Many of us have seen this question many times ( a classic question of almost every intermediate level mechanics course ) where two blocks of the same mass are join two spring balance as follows : ...
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Newton's second law for rotating body with changing mass

Newton's second law for a body with changing mass given as $$F=ma + \frac{dm}{dt}v$$ I need the version for rotational motion. By inspection, it seems that it would be $$\tau = I\alpha + \frac{dI}{dt}\...
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Does the 1/2 coefficient in kinetic energy stem from Newton, the De Broglie wavelength and length contraction? [closed]

This is my thinking. Everything has a De Broglie wavelength. From this the energy of an object can be calculated. Now due to Special Relativity anything with a velocity experiences length contraction. ...
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What happens to the reaction pair? [duplicate]

We know that normal force and gravitational force are not action-reaction pairs but what happens of the reaction force of normal force and $mg$ of Earth?
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Newton’s Third Law When Someone Jumps on an Egg [duplicate]

I’ve been considering the applications of Newton’s 3rd Law and most of the examples I have seen shown to me I completely understand. For example, I understand that if an individual was to push against ...
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1answer
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Energy of Mass Spring System with Mass of Spring Account [duplicate]

I am supposed to arrive at the following conclusion for total energy for a spring mass system with mass $M$ spring constant $k$ and spring mass $m$. $$E = \frac{1}{2}(M + \frac{m}{3})v^2 + \frac{1}{2}...
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How would planets stay in orbit if they sped up? [duplicate]

How would a planet stay in orbit if it sped up? When a planet speeds up, the centrifugal force increases. This makes them move further away from its star. The gravitational force also decreases with ...
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Normal force shift for ball kept in cavity

Adapted from JEE advanced paper-1 of 2020 If you see the left side of the Planck which the ball touches, it seems so that as we vary $\theta$, the contribution of the force from that point of contact ...
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1answer
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In freestyle swimming does flutter kick recovery causes sinking?

As per my understanding in flutter kick, we kick downwards and the water pushes the swimmer up. However, in flutter kick the swimmer is also actually kicking the water upwards when recovering from the ...
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How can work done be equal and opposite when the forces are unequal and object travels the same distance

Let's suppose we have a spring fixed to a wall, attached to a block and nothing is said about the forces acting on the block or spring. It's known that if the block is displaced in the positive ...
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An object on top of a rotating mass like earth

Why do objects fall down in same place on the rotating earth? I get that newton's first law is the reason an object falling on a high speed train will maintain the same velocity as a train and ...
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Is it possible to find $k$ through integral? [closed]

An object (mass m = 0.50 kg) is moving along the $x$-axis, with a velocity of v0 = 1.6 m/s. At t0 = 0,the moment at which the object is in the origin, a force F = −k*t^3, starts to apply to it. Here k ...
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Newtonian mechanics vs. Pressure in Flight [duplicate]

Which one is better to describe lift of a plane wing: Newton's third law of motion: (The wing applies a force on air and the air applies an equal and opposite force on wing - which causes lift.) OR ...
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Force from time and velocity

Let's say I have a goal velocity $(v)$. In $n$ amount of time $(t)$ (let's say two seconds). What is the formula for finding the amount of force I would need (not counting other forces like drag/...
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The direction of the velocity of a body can change when its acceleration is constant. How is it possible since acceleration is a vector quantity?

As we already know that acceleration is a vector quantity which means that it has both direction as well as magnitude. It can also change given any one of the two or both (magnitude and direction) ...
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How do Hurricanes Form?

I'm an Undergraduate Physics Student and I just went down the rabbit hole of asking "What's the Physics of Hurricane Formation?" when I discovered a few things and came up with even more ...
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Conservation or energy problem. What am I doing wrong? [closed]

For a given ion with a charge of $+1$ being accelerated by $U$ volts the distance it travels in a time $t$ is $d$ given by: $$d = v_0 t + \frac{1}{2} a t^2$$ for $v_0=0$ $$a = 2\frac{d}{t^2}$$ and for ...
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Definition of Generalised Coordinates: Confusion with Notation

My analytical mechanics lecturer gave a definition for Generalised Coordinates today, it is as follows: Generalised Coordinates: Let $(q_1,q_2)\in\Omega\in\mathbb{R}^2$ such that $x=x(q_1,q_2)$ and $...
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2answers
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Conservation of angular momentum in an inelastic collision

I have a question about the second method used to solve the problem above. The moment of inertia with respect to the stick's midpoint after the collision is $ml^2/12 + ml^2/4$ or $ml^2/3$ so the ...
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Equation of motion of a classic inverted pendulum in free fall

I was thinking in this interesting problem: Suppose we have this inverted pendulum: But without this control force $F$ and the system would by loose from a height $h_0$, with initial velocity $0$ ...
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2answers
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How to solve the force acting on the box which is in equilibium? [closed]

I did this exercise and it was quite hard, so I decided to come here to ask if my solution is correct. I'm not too sure if my answer was right. Question: A man presses horizontally against a box ...
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Minimum speed separation when two mass move [closed]

question image answer is a c. i am conserving momentum, engergy but not getting c option. I am attaching the question image.
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5answers
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Conflicting intuitions about free fall

So I just started studying physics recently, and I came up with a question that I'm not sure how to solve, and I think it may be because of some fundamental misunderstanding. I don't want anyone to ...
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A simple doubt regarding spring potential energy

A conceptual problem. Suppose we have a spring whose stiffness constant is $k$. The spring is attached to a wall and the other end is fastened to a block. If we pull the block by an external force ...
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Trouble understanding a kinematic equation [closed]

Here's the problem: A ball is thrown straight up from the edge of the roof of a building. A second ball is dropped from the roof $1.00$ s later. Ignore air resistance. If the height of the building is ...
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A block of mass m is attached to two unstretched springs of spring constants k 1 ​ [closed]

This is a question from my module of chapter work, power and energy where i am not able to do this question involving spring force .please help in solving this eith usage of concept related to it . ...
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What is the conversion ratio of linear to angular momentum when a ball hits a rod in space?

If the ball hits the rod at 90 degrees then the rod will start spinning, while also following the original trajectory of the ball. On what factors does the ratio between the two types of momentum ...

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