# Force applied Definition and 39 Discussions

In lithic analysis, a subdivision of archaeology, a bulb of applied force (also known as a bulb of percussion or simply bulb of force) is a defining characteristic of a lithic flake. Bulb of applied force was first correctly described by Sir John Evans, the cofounder of prehistoric archeology. However, bulb of percussion was coined scientifically by W.J. Sollas. When a flake is detached from its parent core, a portion of the Hertzian cone of force caused by the detachment blow is detached with it, leaving a distinctive bulb on the flake and a corresponding flake scar on the core. In the case of a unidirectional core, the bulb of applied force is produced by an initiated crack formed at the point of contact, which begins producing the Hertzian cone. The outward pressure increases causing the crack to curve away from the core and the bulb formation. The bulb of applied force forms below the striking platform as a slight bulge. If the flake is completely crushed the bulb will not be visible. Bulbs of applied force may be distinctive, moderate, or diffuse, depending upon the force of the blow used to detach the flake, and upon the type of material used as a fabricator. The bulb of applied force can indicate the mass or density of the tool used in the application of the force. The bulb may also be an indication of the angle of the force. This information is helpful to archaeologists in understanding and recreating the process of flintknapping. Generally, the harder the material used as a fabricator, the more distinctive the bulb of applied force. Soft hammer percussion has a low diffuse bulb while hard hammer percussion usually leaves a more distinct and noticeable bulb of applied force. Pressure flake also allowed for diffuse bulbs. The bulb of percussion of a flake or blade is convex and the core has a corresponding concave bulb. The concave bulb on the core is known as the negative bulb of percussion. Bulbs of applied force are not usually present if the flake has been struck off naturally. This allows archaeologists to identify and distinguish natural breakage from human artistry. The three main bulb types are flat or nondescript, normal, and pronounced. A flat or nondescript bulb is poorly defined and does not rise up on the ventral surface. A normal bulb on the ventral side has average height and well-defined. A pronounced bulb rises up on ventral side and is very large.When explained visually, the bulb of percussion is visible on the ventral face as opposed to the dorsal face (where it is smoother) and considered to be on the "inside" of the parent core. The bulb of percussion is the primary feature that identifies the ventral surface of a flake or blade artifact. Locating its position reveals which is the proximal end of an artifact. Along the proximal end there may be the formation of ripple marks. These ripple marks allow for the direction traveled by the applied force through the lithic when it was detached. Typically, the striking of the flake is produced by knapping (or flintknapping), a process in which requires the user to chip away material from high-silica stones like "flint" in a carefully controlled manner with special tools to produce sharp projectile points or tools. A common characteristic that is associated with the bulb of applied force is a bulbar scar. This scar is from a small chip or flake on the bulb. This is known as an eraillure flake scar. It is produced during the initial impact of flake removal. Occasionally, there is more than one contact point on a striking platform which creates a series of superimposed waves. The eraillure flake is a chip removed through contact of a dominant force wave that creates the conchoidal flake and inferior waves. Bulb of applied force is not produced by bipolar technology or wedging initiation.

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1. ### Force to apply to a loop moving away from a current-carrying wire

What I have done: (1) ##\Phi(\vec{B})=\int_{S}\vec{B}\cdot d\vec{S}=-\frac{N\mu_0 il}{2\pi}\int_{s=h}^{s=h+l}\frac{ds}{s}=-\frac{\mu_0iNl}{2\pi}\ln(\frac{h+l}{h})## so ##\mathcal{E}=-\frac{d\phi(\vec{B})}{dt}=-\frac{\mu_0iNl^2v}{2\pi h(h+l)}## so...
2. ### B Calculate needed dimensions of table - Center of mass, levers etc

My high school physics days are long ago ;) This is not homework, well, other than it is work, at home. For a real application: Very space constrained "workshop", got a bench drill press, and want to build a table on wheels for it, to be able to move it into a corner when not needed. Those...
3. ### Two forces acting on an object given in vectors - SOLVED

I tried splitting the forces up into F1 and F2 making Newtons second law equation into F1+F2=ma. Then I added over the the first force given. multiply the mass to the acceleration terms to get F2= (m*ai + m*aj) - F1
4. ### Estimating the damage to a material based on force or kinetic energy

I'm programming a game in which I'd like to simulate the real world physics of an attack using primarily medieval style weapons. Think dwarf fortress, but rather than assigning damage numbers we're calculating force or kinetic energy. Getting that much is easy enough since I can find the mass of...
5. ### What is the magnitude of the average force?

Homework Statement An athlete on a sled is moving with a speed of 3m/s across a pond with ice. If the total mass of the sled-athlete system is 95 kg, what magnitude of force is required to bring the sled to rest in 15 seconds? Homework Equations Force acting = change in momentum/time that...
6. ### I Force problem - how the force interacts with time

Hello there, i have a confusion about the force concept itself because when i look dimensionaly i see that N = kg.m/s^2 but i do not understand how the force interacts with time. Is it just about where the object and what is the net force on it due to a reference frame at that moment ? Or...
7. ### Calculation of the weight of an insect floating by surface tension

Homework Statement The surface of a liquid is just able to support the weight of a six-legged insect. The leg ends can be assumed to be spheres each of radius 3.2 × 10−5 m and the weight of the insect is distributed equally over the six legs. The coefficient of surface tension in this case is...
8. ### Which is harder to pull apart, a circle or a triangle?

In deciding which shape of ring I should use to secure an anchor to an anchor trolley I came across two choices, a circular ring or a triangular ring. While either will surely work, I began to wonder which would be more difficult to pull apart. Most of the information I found is about forces...
9. ### Trajectory of a particle under the given force

A particle of mass m in xy plane is attracted toward the origin with the force \begin{align}\vec{f} = - \frac{k^{2} m}{r^{6}}\vec{r}\end{align} where ##\vec r## is position vector of particle measured from origin. If it starts at position ##(a,0)## with speed $$v=\frac{k}{\sqrt{2} a^{2}}$$...
10. ### B F = dP/dt on subatomic particles

I am trying to code a simulator for fundamental particles. The problem is that on a subatomic level, force works differently than on a macroscopic level. Then there is also the problem of Heisenberg's Uncertainty Principle. How is a force applied to a subatomic particle? I did some research and...
11. ### How can I measure the force applied to something?

Homework Statement For a personal project I am doing, I want to test a range of forces in the horizontal direction, and see how the device I created reacts at different forces. So for example, if I want to apply 5N specifically to a device, to see how it reacts under that force, how would I go...
12. ### Magnet's force on a metal ball

As one know, the force on mangnetic dipole in magnetic field is $$\vec F = (\vec p_m\cdot \nabla) \vec B_0$$, where B_0 -- external field. Let consider a some magnetic matherial with permeability \mu. The magnetization of matherial is $$M = (\mu - 1) H$$ (in SI units) and by deffinition M =...
13. ### Coefficient of Friction when Normal Force is Reduced [HS]

Homework Statement A 5.0kg block of wood sits on a table with a string running over a pulley suspending a mass. The largest mass that can be suspended without moving the block of wood is 0.75kg. a) Calculate the coefficient of friction in this case. b) What type of coefficient of friction has...
14. J

### Automotive Simpler force sensor

Is it possible to use a liquid oil filled sealed chamber with a movable membrane connected to a pressure sensor to measured the force applied to the membrane? The reason is have a simpler solution to measured the force.
15. ### I Splitting force vectors into components

Hi I am studying force components on a inclined plane. I understand the concept of breaking vectors into X , Y Components relative to the horizontal plane however what I can't seem to make sense of is how the ratios of a triangle and the main input force being the hypotenuse of the triangle...
16. ### Force of Wind from these variables

Homework Statement I have a strip of foil with an area of 10 square cm and a mass of .561392 grams. The length of the foil is 5 cm and the width is 2 cm. The foil is hanging from a pivot point at the very top. The foil rotates 17 degrees backwards from where it started. The foil is in a sealed...
17. K

### Force exerted on a chain of wagons pushed by a car. . .

Imagine a car that weights 1000Kg. Its engine pushes it forward with a force of 3kN. So the car is accelerating at 3m/s^2 (imagine there are no friction). After 100 seconds (the speed of car at that moment is 300m/s, very realistic), the car hits a wagon that weighs 1000Kg, that is on rest. And...
18. A

### Pascal's Law Problems

Homework Statement The large cylinder in a hydraulic press has 3 times the surface area of the small cylinder. What force should be applied to the small cylinder to create a lifting force of 7200 Newtons In a hydraulic-brake system, a force of 25 N can be applied to a surface area of 5 cm^2...
19. ### Torque and force question

Question that’s been boggling my mind. If you have a 1 ft torque wrench and your tightening your wheels on you Car and apply a force of 70 pounds 1 ft from the nut I’m applying 70 pounds of downward force on the nut but applying a much larger torque to the nut. Now if I apply a 70 lb force 3”...
20. ### How to calculate the maximum RPM of a motor?

Hello all, Just wondering if there is a mathematical formula that calculates the maximum rpm. If I have a fan that puts out 3 pounds of rotational force at stall speed(completely still) at the end point of a 1.5 ft blade what would be the maximum rpm of this fan with the blade attached. What...
21. ### Is true force just "accepted" if it satisfies Newton law?

So I understand the relationship between mass x acceleration=force but all that relationship tells me is "Whatever the force is to accelerate a given mass at a specific unit of acceleration = units of force, and we just accept whatever the unit of force is. example 1/ms² x 1 kg mass = 1 N...
22. ### I Forces applied to a leaning levitating bicycle

Hi! So I'm building an electromagnetic bicycle where the frame is levitating over the wheels, thus reducing the rolling friction to almost zero by removing the bearings. Magnets have also been placed alongside the wheels to provide side to side stability. Black is the frame, red are the magnets...
23. ### Action-Reaction Force for external forces

Homework Statement 1) Are F and F' as shown in figure, the action-reaction forces between the two boxes? 2) What is the action and reaction force between the two boxes? Homework Equations The Attempt at a Solution I think F = 28N and F' = - 28 N Simply adding the action- reaction forces...
24. ### Friction acting on the shot putter

Homework Statement A shot putter with a mass of ##80## kg pushes the iron ball of mass of ##6## kg from a standing position accelerating it uniformly from rest at an angle of ##45^{\circ}## with the horizontal during an interval of ##0.1## seconds. The ball leaves his hand when it is...
25. ### Work done by several forces

Homework Statement Problem # 1 Homework Equations Work done by several forces w=f * d cos theta w=mg n=w The Attempt at a Solution I can't figure out how to solve a) and b) NOT SURE: so my attempt a) f = mg = 30kg*9.8m/s^2 = 294N =magnitute of the force must the worker apply.(NOT SURE)...
26. ### Aquarium on a train during braking

Homework Statement On a train, there is a passenger who has an aquarium, filled with water. The aquarium's size: 40cm x 25cm x 25cm, and is filled with water up to the height of 20cm (5 cm remaining) What is the maximal deceleration of the train, such as the entire volume of water will remain...
27. ### Work calculated for a force not producing displacement?

If a force acting on an object displaces the object, then why do we calculate the work done by all the forces acting on the body (those which did not cause the body to move as well as the force which caused the body to move) instead of the work done only by the force responsible for the...
28. ### B Can force be applied in vacuum?

Is the capability to apply force dependent on the medium.Suppose two human beings are placed in vacuum.Now, can they apply forces on each other? Also, can force fields such as gravitational and electrical fields exist in vacuum and if so then why?
29. ### Force on a ferrous object inside a non-uniform magnetic field

Hello everyone! I want to know how to compute the force applied on ferrous inside a non-uniform magnetic field, to make it easier, let's assume that the field direction is constant, and the magnitude decreases linearly. Now, I know that ferromagnetic material inside a magnetic field will...
30. ### Applied force of a ball on a glove

Homework Statement A 0.145 kg baseball traveling at 35.0 m/s strikes a catcher's mitt which, in bringing the ball to rest, recoils backwards 0.11 m. What was the average force applied by the ball on the glove Homework Equations Fnet=ma or F=ma The Attempt at a Solution I am honestly so lost...
31. ### What is the optimum wing angle and corresponding travelled?

The forces acting on the glider are the gravitational force, the lift force and the drag (air friction). The drag () and lift force () are a function of the angle that the wings have with the gliding direction. =122 with: =0.1+3∙10−32 =122 with: =0.2+0.1− 3∙10−32 In the above equations, is in...
32. ### Velocity after force applied for 0.01 s

Homework Statement A ball(1kg) at rest was hit by a stick to set it in motion. Assuming Force (10N) was applied by a stick, and stick remained in contact with the ball for 0.01s. Ball moves from A to B (10m) in time t. Find, a) Velocity at B ? b) Time t ? (assume frictionless surface) Homework...
33. ### What are the components of an applied force?

Something said in my physics textbook really confused me. The following was written : "Applied Force is our label for a contact force that a person exerts. When an applied force acts at an angle, it is actually a combination of two forces : normal and friction. The component of the applied...
34. ### Physics of bullet impacts, I wonder if anyone can help?

If I have a bullet with 700 Joules KE, the mass is 0.008036m, velocity 417.39m/s, momentum p=3.35kg-m/s Kinetic energy is the ability to do work, Kinetic energy converts into FORCE...so yes KE will exert a force...which will do work, as to do work requires force and distance. Thus, when the...
35. ### Minimum force to make box slide down slope

Homework Statement If m=5.0kg, φ=30◦ and μs =0.87, what is the minimum force needed to make the box slide down the slope? [/B] Homework Equations force of status friction is less than or equal to the normal force multiplied by the coefficient of static friction F,normal=mgcosφ The image...
36. ### It's a work and energy question

1. The problem statement, all variables and given/known force F = (4x i + 3y j) acts on object as it moves in the x direction from the origin to x=5m. What is the angle between the force and the displacement Homework Equations I'm not really sure since I have no idea The Attempt at a Solution...
37. ### Why can't I show Newton's Third Law by different means?

Homework Statement A small mass (1 kg) sits next to a larger mass (3 kg) on a table. A force of 5 Newtons pushes from left to right on the system while a force of 3 Newtons pushes from right to left on the system. Am I justified to conclude that the net force on the larger block has magnitude...
38. ### Min force to lever to lift weight

Homework Statement Homework Equations Concept of couple? The Attempt at a Solution First, I calculated the couple about disc, though I'm not sure if I can use this approach. Since 900 N is pulling the string of pulley downwards, I take the couple about disc as 900 x 0.4, which gives me 360...
39. ### How to find the force of friction?

Homework Statement What is the force of friction on the elastic powered car as it rolls across a smooth surface? GIVENS Displacement= 16.25m, Change in time= 22.5s, G=9.8m/s, Mass= 1kg UNKNOWNS V1=?, A=? Ff=? Homework Equations F=MA, A=V/T, Change displacement=((V1+V2)/2)T) The Attempt at a...