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 discussion of energy, momentum conservation etc., use classical-mechanics, for Newton’s description of gravity, use newtonian-gravity.

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Jumping off a boat vs ship [closed]

Why it is harder to jump towards the coast in a boat than in a ship (more massive than the boat) that is equally near as the boat? I think we should use Newton Law's and this happens because the mass ...
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Playing catch in space?

I was thinking about this on the bus (exam this week :P). What would happen if two people played catch in outer space? Lets say person A and B are in space at rest, A throws a mass m at B, what ...
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Finding minimum force to hold a particle in equilibrium [closed]

A particle of mass $m$ is suspended from a point A on a vertical wall by means of a light inextensible string of length $b$. Find the magnitude and direction of the minumum force $\boldsymbol P$ ...
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Prevent a box from tipping over: height of CG?

I'm on a problem that can be simplified in the following way: A box is placed on a horizontal plane, and is pinned to the ground on one side only such that it can tip over that side. Given a ...
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Finding the Work done

Find the work done for an object to slide down an inclined plane against the frictional force. The answer my book shows is : $$ W = mg ({\mu}_k \cos \theta - \sin \theta) S $$ where S = displacement ...
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Mathematical subtlety in a physics problem

A wagon of initial mass $M$ is moving with an initial velocity $V_o$. Now sand starts accumulating on this wagon, increasing the total mass from $M$ to $M+s$. We have to find the final velocity of ...
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Throwing baseball at a car

For some odd reason, you decide to throw baseballs at a car of mass $M$, which is free to move frictionlessly on the ground. You throw the balls at the back of the car at speed $u$, and at a ...
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54 views

How can we show that pressure is exerted sideways too?

We can show that pressure upward and downward in a fluid is caused by weight of fluid column or volume. A simple derivation of this: ...
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What happens to an orbiting body moving with the Earth's angular speed at various altitudes?

I was learning about inertial frames amongst other things, and I somehow came up with this question. Imagine we have a pole, made of imaginary very strong material that will never bend, placed at the ...
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55 views

Will this sail-based moving system work? Why? [duplicate]

So simple: Will this sail-based moving system work? Why?
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101 views

Is the Fundamental Theorem of Calculus really applicable to the definition of work?

When the force $F$ on an object is not constant, then the work it performs is defined as $$W = \int_{x_0}^{x} F(X)dX.$$ Now, the Fundamental Theorem of Calculus states that $$\text{If}\,\,\, f(x) ...
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Pendulum in Accelerating Elevator

I have been looking for this for quite some time now. A simple pendulum behaves in SHM. Let's put that pendulum in an upward accelerating elevator. The component of the force that acts in SHM ...
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67 views

What if the centripetal force were acting outward?

Centripetal force is the centre-seeking force & is responsible for circular motion. But what if the centripetal force were acting radially outward? What would happen then?
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Center of mass after explosion [closed]

How he treated the center of mass as if it is still in the same place , is not it supposed to change after explosion ? and is not explosion destroying the closed system? i mean it represents and ...
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138 views

How did Newton discover the universal law of gravitation?

I am having trouble comprehending how anyone could come up with this formula: $F = \frac{GMm}{d^2}$ Could someone walk me through this?
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Can a piezo actuator have infinite resolution?

See here: http://www.omega.com/googlebase/product.html?pn=LD400-1&gclid=CjwKEAjw77OhBRCJ7Onfp_HNtwYSJACZqHAWVTfW1BO4RSfSVjz9P3Q4FoPTvZ2r3NIc2W1uEthVhBoCgUHw_wcB I don't think so. Do they just ...
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112 views

Why do we use less fuel by driving at constant speed?

It is common practice to drive at constant speed as much as possible to reduce fuel consumption, or at least to avoid "pumping" on the throttle (at frequencies high enough that the lowpass filter does ...
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97 views

Does Newton's first law apply also to non-newtonian physics?

I think I understand than an example of Newton's first law (intertial frames) would be a single asteroid in vaccum with no other bodies around, a comet in such free space or likewise. Then I think the ...
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If a body is floating in a static fluid, then the volume of the displaced fluid equal to the volume of the inmerse part of the object (proof)

Suppose an arbitrary body is floating in a static fluid, either totally or partially immersed in it, then the volume of the displaced fluid equal to the volume of the immersed fraction of the object. ...
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154 views

Deriving Time from Acceleration, Displacement, and Initial Velocity

I know the equation for displacement as a function of time is $$\vec{s} = \vec{v_i} \Delta{t}+\frac{1}{2}\vec{a}\,(\Delta t)^2$$ I need to solve for $\Delta t$ I'm having problems rearranging to do ...
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131 views

From Paris to … London [closed]

(Excuse the pun in the title, couldn't resist) Paris and London are connected by a straight underground tunnel, as shown in the diagram below. A train travels between the two cities powered only by ...
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116 views

Does the coefficient of restitution matter in a collision?

Suppose two particles are colliding. Let initial velocities be $u_1$ and $u_2$ .Their final velocities are $v_1$ and $v_2$. Now $u_1$ and $u_2$ are known. By intuition I can understand that $v_1$ and ...
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Can friction be brought in to zero value by means of laboratory experiments?

By newton's first law, an object will continue to be in the state of motion of rest until and unless an external force is acting on it. To prove or verify it experimentally today, is there any way out ...
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80 views

How to calculate energy to start movement?

So let me try to explain a little bit. Lets say I have a robot on wheels. I want this robot to push a block. Lets say the force to produce in order to move that block is 100N. How much energy will I ...
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98 views

Is friction always constant?

Can the norm of the friction force change with time? Notice I said the norm which is in Newtons, can it change with time? Sorry if the question seems a bit confusing but I've done my best to explain. ...
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How do internal forces affect motion?

As per newton's first law, only an external force can bring any change in the acceleration of a body, internal forces cannot. So, when we apply brakes to an accelerating car, aren't those ...
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159 views

Why isn't angle of launch used in this kinetic energy equation?

Question: A stick is thrown from a cliff 27 m high with an initial velocity of 18 m/s at an angle of 37 degrees above the horizontal. a) use the law of conservation of energy to determine the speed ...
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87 views

Why is it easier to turn a heavy hanging object?

Assume if we had a 2 tonne weight placed on ground attached with a rope that we can use to turn the object around. It will immensely hard to turn that object around by pulling the rope. However, if ...
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66 views

Horizontal force on elevator?

I would like to ask the following: If an observer travels up or down in an elevator on earth, does he experience a horizontal force due to earth's rotation?
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82 views

Sign of Potential Energy

The mass is released at height $h$ above the spring, how far will the spring move? $E_i=mgh, E_f= kx^2/2+mgx$...why the second equation isn't $ E_f= kx^2/2-mgx$? Since it is below the "zero".
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Confused about Impulse

Encountered a problem that involves impulse while studying for my exam and I'm not sure how to even approach it. I know that momentum is conserved, but I'm not sure how to relate that to avg force. ...
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67 views

Homework Question involving Momentum [closed]

I'm trying to solve a homework problem as review for an exam I have tomorrow and I was wondering if someone could help explain it to me. It is as follows: You are at Lowe’s shopping for bricks ...
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124 views

Can walking provide electrical energy?

This is more of a theoretical question, but is it possible to convert the energy you use to walk into electrical energy to say, power a light bulb?
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How to plot $(x,y)$ coordinate of projectile motion (with air-resistance)? [closed]

I am trying to plot a graph to show the difference in projectile motion when it has air-resistance and when it doesn't have air-resistance. I set the mass, $v_0$ and $\theta$ as constant I can plot ...
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244 views

Toppling of a cylinder on a block

A uniform cylinder rests on a cart.The height and diameter is given.coefficient of static friction is given.How can i find the minimum acceleration of block such that the block topples? Morever what ...
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204 views

Mosquito in a Bus [duplicate]

My Question goes like this: If a mosquito inside the bus wants to move from back to front, will there be any difference if the bus is stationary or moving (ie extra effort in the latter case?)? ...
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Is potential energy and “work done” the same thing?

Is potential energy and "work done" the same thing? If they are not one and the same thing then why is potential energy always associated with "work done"? Could you explain me with some examples?
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Why isn't the gravitational acceleration taken in to account when determining the net acceleration of a person riding a Ferris wheel?

Say for example you have a person riding a Ferris wheel. What is the difference in his acceleration (towards the center) for when he is at the highest point to when he is at the lowest point? So the ...
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796 views

Direction of friction when a car turns

When a ball moves to the right, friction acts to oppose the motion, in other words, to the left. However, when a car travels around a bend, the friction acts in the perpendicular direction to the ...
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Constant Velocity 'Force'?

According to Newtons second law: F = ma, if acceleration is zero then the force must be zero, but assuming you have an object moving with a constant velocity of say 2 m/s, and that object strikes you, ...
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String tension in vertical circular motion

Suppose that I have a point mass attached to a massless string and I am rotating it vertically. That means The mass is in uniform circular motion and the path of its motion is vertical circle. How ...
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132 views

Distance travelled in spaceship Newton vs Einstein

If you get in the canonical 1G windowless spaceship and accelerate for 5 years as determined by your trusty wristwatch, then decelerate for 5 years, then decide its time to see where you are would the ...
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341 views

What happened to potential energy?

I was learning how charge can be virtue of a body's potential energy.Meanwhile,I was hung by this question. [gravitational and other forces except coulombic,are assumed to be not acting on the ...
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287 views

Conservation of angular momentum

We were learning about angular momentum in class today, and although it sort of makes sense, it's much harder for me to think about than linear momentum. So from what I can tell: Angular momentum ...
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393 views

Why is kinetic energy only “often $(1/2)mv^2$”?

I am reading the first few pages of Nakahara and refreshing my memory on physics I learned a while ago as a physics math undergrad. Nakahara defines a field $F$ to be conservative if it's the gradient ...
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357 views

Collision of two balls [duplicate]

Two balls, with masses $m_1$ and $m_2$ are falling from the heigh $h$. All the collisions are perfectly elastic. Do not consider the size of the balls. $m_1 < m_2$ and lighter ball is on the top. ...
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130 views

Can you justify force calculations using more than one of Newton's laws?

If an object is at rest on a flat surface I remember my school teacher would say, "By Newton's 1st law the normal reaction, R, is mg (mass x g)". Ok, sure this is fine because the object is at ...
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Finding the drag force (Air resistance force) for accelerated ball?

As you know if I want to find the force for an accelerated object I will use the law $F_o=ma$ so I can get the affecting force of it. But there is another force affecting against the object. It's the ...
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Why does a car go down the hill backwards even though the engine keeps running? [closed]

I dont get why a forward gear allows sliding a car backwards. Any ideas? So this is a car with an automatic transmission. The transmission is in the drive mode (move forward). Car is at the slope ...
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478 views

Friction force and contact area [duplicate]

It's usually stated that the friction force is independent of the area of contact (Amontons' Second Law). I've always thought that this shouldn't be true, because the atraction between molecules ...