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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Question please, [on hold]

Why the resultant force is less than the applied force?
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0answers
30 views
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22 views

Quick question on rotational motion

This is a quick one. (AP Physics B 1977): A box of mass M, held in place by friction, rides on the flatbed of a truck which is traveling with constant speed $v$. The truck is in on unbanked circular ...
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0answers
28 views

BASED ON NEWTON'S 3RD LAW [duplicate]

my question is based on newton's 3rd law . An elephant pushes a rabbit with $250 N$ force , then the rabbit should also apply $250 N$ force but the rabbit is only capable to apply $25 N$ force . Why ...
3
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3answers
90 views

Is static friction the only force causing a car to move (without sliding)?

A car is moving without sliding means that the friction between wheels and the ground is static friction. This is the force causing an object to move forward, therefore, its direction is the same as ...
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2answers
42 views

How do I use a free body diagram in this case? [on hold]

In the above cases I want to find the acceleration $a$ for $m_1$. I can do it by considering $m_1$ and $m_2$ to be a system, which would give me $a = F/(m_1+m_2)$. How can I use a free-body diagram ...
2
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2answers
39 views

Why is the centripetal force vector on a banked turn horizontal rather than parallel to the incline?

Why isn't the centripetal force parallel to the inclined surface? It seems like if you were to draw a circle with one point being at the center of the curve and one point at the car the circle would ...
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2answers
69 views

How can gravity have a horizontal component?

$mg$ obviously has no horizontal component, but on resolving it into components it seems to have a horizontal component $mgcos\theta sin\theta$. I know I'm doing something wrong here. How is this ...
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0answers
24 views

How are the tension and acceleration of various strings and masses related in a system having more than two pulleys and more than two masses? [closed]

On what factor does the tension acting in a string depends if all the pulleys in the system are considered to be massless?
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0answers
28 views

What is the maximum speed without skidding on a circular path? [closed]

What is the condition that the body going on the circular path will skid if its speed is increasing at a constant rate, say a? I need a free body diagram too.
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0answers
20 views

Systems of Connected Particles [closed]

What are the all the forces acting on a wedge that is accelerating horizontally carrying a particle that is also accelerating down its slope?
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4answers
71 views

Action is equal to reaction. Then how is a horse able to pull a cart? [duplicate]

Please answer the question in detail. I have tried other websites for answers but was not able to understand properly.
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1answer
21 views

I need help with determining angles after shifting of axis in Free Body Diagrams

I can't figure out by which property of the triangle the angles in shifted axis are also 30 degrees. Vertical angle theorom doesn't work. I drew it again and again. If someone could draw me a ...
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0answers
21 views

Force conversion in a barrel cam-follower mechanism

A barrel cam-follower mechanism consists of a (cylindrical) barrel with a cam track, a cam-follower (roller) inside of the track, a fork connected to the cam-follower and a guide along which the fork ...
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2answers
51 views

Problems with work on an inclined plane

A constant force $F_a$ of magnitude $82.0N$ is applied to a $3.00 kg$ shoe box at angle $53.0^{\circ}$, causing the box to move up a frictionless ramp at constant speed. How much work is done on ...
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2answers
45 views

Question about aircraft/rockets

Lets say that you're sitting an inverted airplane. How do you determine how fast the plane must accelerate in order for you to not fall out?
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1answer
29 views

Why does the water in a bucket stay even when swung around in circular motion? [duplicate]

What are the force that act on the water and which force is responsible to keep the water from falling out?
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1answer
26 views

Stuck on a static equilibrium problem [closed]

This is the problem: "The figure below shows a 25-foot sailboat. The mast is a uniform 119-kg pole that is supported on the deck and held fore and aft by wires as shown. The tension in the forestay ...
1
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1answer
43 views

What component of the payload appears on the cross member? [closed]

I have a set of DIY steps; I've modelled it as the steps themselves "s", a short vertical support "a", a long vertical support "b" and a cross-member "c". Here's a picture: Just to be sure I ...
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4answers
83 views

Draw the Free Body Diagram

Question: Draw the Reaction Force at point P. My Attempt and Reasoning: Since the Reaction or the Normal Force is normal to the surface the solution according to me should be- However, the ...
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4answers
203 views

Normal force on vertical circular motion

I have a couple of questions concerning vertical circular motion. The object shown in the diagram moves with constant speed on the inside of a circle. In point A the normal force points to the ...
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3answers
95 views

How to explain the force applied on this object? [closed]

Sorry for posting such a simple problem but I'm having trouble understanding this concept. In the picture below, we have a force, $ \vec F_{app}$ acting on two objects, A and B. Mass of block A: $ ...
4
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4answers
1k views

What Keeps a Pendulum Moving In a Circular Path?

From the figure, we know that $F_{net} = mg\sin\theta$. Now, this force $\vec{F_{net}}$ is in the direction of the velocity $\vec{v}$ of the bob, both are tangent to the path. Therefore, the net ...
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4answers
84 views

What is the Role of gravity?

I am new to physics and I understand gravity is a pulling force. Let's assume a ball has been placed on the ground. Does gravity has any role after I placed an object (e.g. ball) on ground? ...
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1answer
55 views

$P = h \rho g$ derivation

Here is a snapshot from my textbook : Here only three forces are calculated: The gravitational force The force due to the pressure $p$ on the bottom surface The force due to the pressure ...
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1answer
41 views

How does paddling in the water help a boat move forward?

The way I've seen it explained is like this: it all has to do with Newton's third law. However, the "equal and opposite" reaction predicted by the third law acts on the paddle - which is not ...
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1answer
32 views

Dependence of tension (considering a pulley system) on the mass of loads

Consider the diagram below All circles are pulleys, which are fixed at the ceiling. M represents an engine (with a certain power) that is pulling the cable. C and D are weights. The acceleration of ...
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56 views

Sliding blocks problem

My first post here, so I apologize if this is duplicated elsewhere. It IS a "homework" problem, but it's public domain, a posted exam with answers... ...
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2answers
47 views

Condition for looping the loop

Consider a ball tied to a string and it is imparted a velocity we have studied that condition for looping the loop is that tension at the uppermost point must be zero, but why is this condition ...
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2answers
114 views

Is the work done by friction on an accelerating car zero?

Consider a car is accelerating and its tires are not slipping ,just rolling.what is the force on the car that changes its kinetic energy? Some people say in the definition of work dw=F.dx that dx is ...
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0answers
46 views

Free body diagram of pulley

Is there any difference between the free body diagram of fixed pulley and movable pulley? I've read that both of the rope of fixed pulley and movable pulley have the same direction (both upwards or ...
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3answers
95 views

Free body diagram in sliding blocks situations?

I'm confused about the motion on two blocks sliding one over the other when more that one force is acting on them. Consider two blocks $1$ and $2$, with different masses, with $2$ placed over $1$. ...
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2answers
34 views

Dynamical friction force

Let we have a ladder leaning on the wall. Initially we hold the ladder and as soon as we release it the ladder starts to slide. My question: during the slide, are the friction forces at both ends ...
0
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1answer
51 views

Laws and Intuition for physical problems

So I've been reading the book 'Feynman: Tips on Physics' recently and in chapter 2 (the book is available for free online) he works out the answer for this problem using his intuition rather than ...
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4answers
60 views

How to determine the direction of friction force on FBD?

I am working on the following problem: Note that 0.5*N is the force due to friction pictured in the FBD. When I try to solve this, my intuition is to draw the friction force upwards rather than ...
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1answer
26 views

Electricity problem [closed]

• Two small metallic spheres, each of mass 5 g, are suspended as pendulums by light strings from a common point as shown in Figure. The spheres are given the same electric charge, and it is found ...
3
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1answer
45 views

Free body diagram when forces are not directly in contact with the object

I was trying to use Newton's second law to describe the motion of the following pendulum: However, I was confused as to how to include the spring in Newton's second law. I was able to set up a ...
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0answers
29 views

Free Body Diagram Convention

A classmate and I recently got into a debate that I was hoping could be settled. Is it standard convention to display the net force vector on a free body diagram? Internet searches seem to give mixed ...
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1answer
54 views

Converting loads on horizontal surfaces to inclined surfaces

A textbook on design of wood structures makes the following argument: We have a flat roof snow load $$S_1 = 61.6 \frac{lb}{ft^2}$$. The idea is to convert it to an equivalent sloped roof snow load ...
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2answers
95 views

Free body diagram for two masses on inclined plane with frictions

I'm a bit confused about free body diagrams on inclined planes with frictions. Consider the situation in the picture, where $A$ and $B$ slide togheter on a inclined plane and I want to find a force ...
5
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2answers
181 views

Free body diagram with forces of friction

I'm reallizing that I'm very confused on how to make a free body diagram of forces in some situations where there is friction between two objects. I'll make an example where I cannot figure out what's ...
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3answers
63 views

Conditions for the tension to vary in the rope

What are the conditions for the tension to vary in the rope. I have read below conditions 1. rope has to have some mass 2. rope is accelerating I get the 1st ...
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2answers
76 views

Why do the masses in an Atwood's machine move?

The masses you see on the following picture are $m_1=8$kg and $m_2=12$kg. Also the coefficient of friction between $m_2$ and the floor is $0.25$. What i'm concerned with is that although $m_2 ...
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1answer
59 views

How does Newton's 3rd Law work in this scenario? Why is my reasoning wrong?

I came across this example question in my mechanics book: It's a light scale pan with negligible mass, with two blocks A and B, with masses 0.4kg and 0.6kg respectively. The pan is attached to a ...
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0answers
41 views

Forces acting on a jet pilot [closed]

I found the forces at A and C with no problem, when it came to the forces at B I found the normal force of the seat on the pilot but the forces in the tangential direction got me. The solutions ...
0
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1answer
73 views

Seesaw Physics - Shipping Container House Problem

I'm currently building a house using shipping containers. One of the containers is in a cantilever position, sticking out from the base concrete structure like this: ...
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2answers
81 views

Why don't barbells tip over when a 45 is placed on one side?

A standard barbell is 45 pounds, as is the heaviest weight available in most gyms. When a weight is placed on the side of a barbell, some of the barbell is to the "outside" of the weight, like so, so ...
1
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2answers
93 views

Why can we assume, when dealing with tension, that the mass of a rope is $0$ but still assume that there are forces on it?

I started studying tension and I can't understand the following concept: If I have two objects $A,B$ collegated by a rope, where $A$ applies a certain force $\vec{F}$ on it, I would have that the ...
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0answers
34 views

How forces divide in pulley series? [closed]

I'm trying to solve a question , It's about a lat pull fitness equipment. Here you can see what's the equipment : When someone start pulling down, How do forces divide between two pulleys ? I mean ...
12
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5answers
1k views

What force causes the ball to move up?

Let's consider this super-simple example. The ball (mass $m$) is moving from position 1 to position 2 at constant horizontal velocity $v$ until the ball reaches the red arrow (in position 1, it has ...