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Questions tagged [free-body-diagram]

A pictorial device which analyzes forces present on any body with the use of vectors. Allows easier grasping of problems involving either objects at equilibrium or in motion. Can be used to predict presence of forces.

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Force required to move bar at one end

A uniform bar of length $L$ and weight $W$ rests on a level floor so that there is a uniform contact pressure between floor and bar. A horizontal force $P$ is applied at one end, normal to the bar. If ...
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0answers
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Calculating torque required to rotate a platform [on hold]

I am trying to spec out a motor's torque required to rotate a platform about an axis. The attached diagram makes it better to understand. Dimensions are in cm: I have an arbitrary shaped object on ...
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4answers
42 views

Applying Newton's Laws in a Circular Motion

A child ties a rock to a rope and turns it around describing a circle. horizontal. My Classical Physics teacher has told me that the string cannot be perfectly horizontal, but I don't know why. I ...
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The minimum force required to move the block is [on hold]

My question : A block of mass 4 kg is placed to a rough vertical wall with a normal force of 100N.The coefficient of static and kinetic friction are 0.5 and 0.3 respectively. The minimum force ...
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0answers
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Newtons second law appliance [on hold]

Assume we have one box, and we put another box on it. A box of $m_1=4\ \rm{kg}$ and a box of $m_2=2\ \rm{kg}$. The box with more mass ($m_1$) is in the bottom. What will happen if we apply a force of ...
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1answer
39 views

Proof of the Law of the Lever

Is there an accepted proof of the Law of the Lever? I know of several attempted proofs, such as Archimedes's, but these either are incomplete or do not transfer to the setting of Newton's Laws. (It ...
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1answer
44 views

$mg\cos\theta=N$ or $N\cos\theta=mg$ [duplicate]

I was reading up of centripetal motion when I saw the relation that $mg=N\cos\theta$, as can be seen from http://hyperphysics.phy-astr.gsu.edu/hbase/Mechanics/carbank.html, in the case of a ...
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1answer
38 views

How does Newton's third law work in springs?

So in high school I thought 'if Newton's third law works, why do springs ever move?' In other words, if I pull on a spring, that means a force of the same magnitude is being exerted in the opposite ...
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2answers
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Tension in atwood machine [on hold]

Pretend you have an Atwood machine with a frictionless pulley system. On one end you have a very very heavy mass and on the other end, you have a basically negligible mass such that the combination of ...
2
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1answer
61 views

Is friction affected by gravity?

Some people said that moving a car on the moon would make the tires spin a bit more compared to Earth's. But then I started thinking that if static friction and gravity are perpendicular to each other,...
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0answers
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Find forces applied that supports a block [closed]

The pen of the figure hangs a block of mass $m = 1020~kg$. Find the modules of the forces applied in supports $A$ and $B$. I did the following, where $T_A$ is tension at point $A$, $T_B$ is the ...
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0answers
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Sliding between three blocks kept on a smooth surface? [closed]

Here is how I tried to solve In the answer the mass of (md) is 3m but I am getting m. I have a conceptual mistake I am not getting it . Please help .
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1answer
52 views

Resolving forces on inclined circular motion

When resolving forces vertically and horizontally in a problem where a car is going around a banked bend, why do you consider the components of the normal force? Shouldn’t the normal force just cancel ...
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1answer
92 views

Are we able to move in a room with vacuum and no gravity? [on hold]

Let's assume this room would exist and we stick in the center. Would we rotate infinitely if we pull our legs as hard as possible to our chest or what exactly would happen? Aside from the fact that ...
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3answers
25 views

Forces in a staically determinate cantilever Truss, why some experiences compression while others experience tension?

The Redundant Truss Apparatus is constructed with units of basic triangular pin-jointed. At joint 1, it is fixed firmly due to a support. At joint 2, it is fixed to a movable support. Suppose at ...
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1answer
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$μ = \tan\theta$ - Why? It makes sense mathematically, but if it's based on the materials how does that work?

We were presented with a problem in physics today in which we calculated that the coefficient of static friction is equal to the tangent of an angle This is on a ramp using the laws of friction. My ...
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0answers
45 views

Force on arms climbing stairs [closed]

What are the forces in each arm a person experiences while lifting oneself between parallel bars 1/2 foot above the ground? Is the formula F = W * h, where W is the weight of the person and h is the ...
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1answer
120 views

Friction between two blocks on top of each other

I am a little bit confused to the concept of friction between two blocks on top of each other. there could be two situations: the first situation is when all surfaces are frictionless including that ...
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4answers
53 views

Newton’s Third Law Intuition Example Question and Clarification

Assume that I was in space, where there is no friction. Also assume that there were two objects at rest: myself and a matchbox. Does this mean that, by Newton’s Third Law, since there is no friction, ...
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4answers
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Does $m$ in this problem refer to the total mass of the system or just the mass of a single body?

I am trying to figure something out in this problem: I am having trouble with these types of problems because often I don't understand which forces I need to consider when setting up $F=ma$. Here is ...
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1answer
39 views

Connected system

two bodies having masses M1 and m2 (M1>m2) are attached to the ends of a light inextensible stringpassing over a smooth frictionless pulley.when the system is released M1 moves downward and m2 move ...
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1answer
46 views

Normal force in uniform circular motion [duplicate]

When we consider a person on a ferris wheel, the forces acting on him at the top are the normal force and gravity. The acceleration of the person is downward (towards the center), so by Newton's ...
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4answers
65 views

Loading condition for analysis

The problem is shown in Fig. 1. I want to analyze Link 1 by applying load only to link 1. Need to know what is the right approach for loading condition in the software. Approach 1 or Approach 2..?. ...
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1answer
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Earth as a perfect sphere and an object trying to stand still

I have imagined the Earth as a perfect sphere with uniform mass density and I put an object somewhere between the equator and the north pole at rest with respect to earth. And also in my imaginary ...
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1answer
41 views

Physical meaning of same pressure on the same plan (hydrostatic paradox) with different weight above them [duplicate]

In this picture the points on red have the same pressure because the weight of the fluid is the same above them. But according to pascal law the point on black must have the same pressure(both 3 ...
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1answer
93 views

According to newton's laws, why do the two different masses of an Atwood machine move in opposite directions?

Consider an Atwood machine with two different masses $M$ and $m$ such that $M > m$. When trying to find the acceleration of that system, all solutions I've found go like this: There are 2 forces ...
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2answers
121 views

Speed of the rotating block [duplicate]

Problem: A block tied to a string is rotating with an angular velocity $\omega$ on a frictionless table. The string passes through a hole in the center of the table. If the string is pulled and the ...
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3answers
28 views

Rolling friction and motion [duplicate]

The frictional force in a motion of a rolling body is along the direction of motion. Then what stops the motion of a rolling body?
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3answers
78 views

Is there any naturally occurring downward force that exists on Earth other than gravity? [closed]

For a project, I was wondering whether or not it is possible to increase the net downwards force acting on an object so that you are able to manipulate its weight.
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1answer
41 views

Free body diagram representation of coriolis force

In many problems,horizontal and vertical components of coriolis force are taken into consideration. But I really don't know how to fit these components into a free body diagram. Can anyone help me out ...
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2answers
40 views

From Where Did The Table Get Energy? [duplicate]

When a block in resting on a table (the table is on Earth) the table stops the block from going more down, from where does it get the energy to apply a force opposite to gravity?
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1answer
74 views

Forces acting on an orange placed on a table in equilibrium [closed]

An orange sits on a table in equilibrium. What forces are acting on it? What is the reaction force to each of the forces acting on it? What are the action and reaction pair?
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2answers
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Why is the restoring force not zero at the equilibrium position of simple harmonic motion?

The restoring force is applied in order to take the body it's equilibrium. Then in a SHM why in the mean position restoring force maximum rather than being zero as it has reached equilibrium. (After ...
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1answer
36 views

Would a $y$ axis affect the $x$ axis in a free body diagram? [closed]

Would a $y$ axis affect the $x$ axis in a free body diagram? like forces and all that can you add them or use them together. Or they do not interfere each other?
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2answers
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why is friction acting towards the centre in a level curved road? [duplicate]

We all know that friction is a force that opposes motion and is applied in the opposite direction of motion, but in a leveled curved road it becomes the centripetal force and pulls towards the center. ...
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0answers
32 views

Understanding forces in Loop movement

I'm failling to understand this concept on Newton's Laws in a loop. Suppose that you have a body going in a straight line and finds a roller-coaster. At the exact point it's going to enter the loop ...
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1answer
55 views

Tension in pendulum [closed]

I am asked to calculate the tension in the rope of a pendulum at (a) its initial position as well as at (b) its lowest position. $L = 3 m$ $α = 10^o$ $mass = 2kg$ (a) For the intial point I used ...
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What is the equation for optimal banked turns?

In physics class I learned that to turn is to accelerate. Since High School I’ve taken that to mean: On a flat surface, the direction of a non-accelerating object must be a profile of that object’...
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2answers
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How can the same tension pull both the mass and the pulley?

So I have this problem: and I've drawn free-body-diagrams of pulley b and mass 2 I couldn't help but notice that the tension ...
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1answer
138 views

Why is tension in a rope the same at every point?

So, I had this lecture where it was explained that if the pulley is friction-less, then the tension on any point of the rope is going to be same. I can understand the friction-less part, as pulley is ...
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2answers
89 views

What is the force that actually propels a human forward in a train or car?

This question arises after much debate with some fellow engineering students and we are looking for somewhat of a theoretical answer more than anything. When you are sitting in a train or a car, what ...
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1answer
64 views

How does gravity effect to aircraft in sky?

Aside aerodynamics and buoyancy, Is there a simple way to explain how gravity is negligible in flight paths using free falling body diagram? In a parabolic trajectory,we know that at max height, ...
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4answers
90 views

How can pressure act in both the up and down direction?

It says in my textbook that pressure is a vector. So how does it act both in the up and down direction in the same body of water as seen in this image?
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2answers
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Archimedes Principle $\Delta M$ formula

i'm trying to determine a formula for $\Delta M=M-M_{apparent}$ in terms of $\rho_o , \rho_w , M$ for a fully submerged object and I have no idea where to begin. I have attempted to draw a force ...
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1answer
41 views

Virtual work - Tension in a string

I am confused about the way Tension or Thrust is used in equation of virtual work. I mean whether to use $ T\cdot dr$ or $-T\cdot dr$ (work done by tension). For instance in the below case : A ...
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1answer
84 views

Ladder and friction (wall and floor) [closed]

Here there is a problem and the proposed solution: UPDATE: I can't understand why getting the maximum friction to solve this kind of problem when it is known that static friction, depending on other ...
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8answers
137 views

Why doesn’t friction cause a ball to move in the opposite direction?

When we toss a ball onto a wall, upon collision, by Newton’s third law, the reaction force on the wall would cause the ball to rebound, coming back to us. This is because this force is in our ...
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2answers
58 views

What are the forces acting on a book kept on the ground? [closed]

If we exclude the motion due to the rotation of the Earth, what are the forces acting on the book? I know about the force of mg acting on the book and its opposite acting on the Earth, but I have some ...
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3answers
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Internal and external forces

When a person lifts a book while standing on the earth's surface. Why is his force considered external to the book-earth system? Isn't his force internal like the case of the forces that cause the ...
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2answers
63 views

Maximum tension in a rope [duplicate]

Lets say I have a siccative object that’s attached to a rope and it’s moving in a vertical circular motion around some circumcenter. If along the motion the rope will happen to reach maximum tension, ...