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.
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...
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...
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...
Homework Statement
I think that the equation for the force someone exerts on their bike pedals or the force forward is stated below. can anyone confirm this is true?
Homework Equations
Fapplied by rider = (weight of rider) (Radius Crank /Radius Tire) (Gear Ratio)
The Attempt at a Solution
Homework Statement
your car is stuck in the mud and you can’t pull hard enough to get it out. You do, however, have a long cable that you connect taut between your front bumper and the trunk of a stout tree. You now pull sideways on the cable at its midpoint, exerting a force f. Each half of...
Homework Statement
A ball of mass m hangs vertically from a massless string experiencing a tension T. What force is required to pull the ball out to an angle theta from the vertical?
1) mgsin(theta)2) mgcos(theta)3) mgtan(theta)4) 2mg tan (theta)5) mg/cos (theta)
Homework Equations
no...
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...
Homework Statement
Force is applied to a body from A to B, and then withdrawn.
Question: What happens after B ?
1. Will the body keeps accelerating after B ?
2. Will the body keeps moving with constant velocity after B ?
Consider both friction and frictionless surface.
2. The attempt at...
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...
If you place an solid object on a fluid, is the force it applies to the fluid equal to the buoyant force? I would have thought that it applies a force equal to its own weight but that would mean that the force applied to the object by the fluid, the buoyant force, would not be equal and opposite...
Homework Statement
A cart travels up a hill at a constant velocity in 2.5 (s). What power is developed by the cart?
m=120 kg
meters=12m
θ=21°
Homework Equations
P=w/t
w=F(parallel)×meters×cosθ
The Attempt at a Solution
P= w/t= Fdcosθ/2.5= F(12)(.93)/2.5= 11,2F/2.5= 4.5F
How do I find F?
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...
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?
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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...
Homework Statement
The mass of A is 5kg and the mass of B is 10kg. If the acceleration of A is 2m/s^2 which is smaller than acceleration of B, where A is placed on top of B, then the value of frictional force applied by B on A is:
A) 50N. B) 20N. C) 10N. D) None of these
Homework Equations...
Homework Statement
I'm making a program that draws a graph of the weight of an hourglass. Obviously at first we know the weight, and as the grains begin to fall it decreases by the amount of mass in free fall. However I ran into a problem when the grains begin to hit the bottom. It's impossible...
Homework Statement
Another question regarding pool. I need to know how much force applied is given from the cue to the ball as well as force of friction
OF CUE:
a=56.55m/s2
vi=0m/s
vf=3.28m/s
d=.0953m
m=.55kg
BALL:
m=.17kg
*not sure whether to use distance traveled during contact or of the...
1. Homework Statement
h = 17.2 cm
A = 12.32cm2
E = 410 MPA
Fapp = 6130 N
2. Homework Equations
Stress
σ = F/A where F is force applied and A is cross sectional area of side where force is applied
Strain
ε = ΔL/L where L is the length of the bar and ΔL is the change of length of bar
Young's...
Homework Statement
A force of (4,-2,7) is applied to an object lying in the x-z plane that angles 32 degrees above the positive x-axis. Find the work done by this force over 3.0 meters of motion.
My confusion is due to the solution my textbook gives. It says the displacement is in the x-y...
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...
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...
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...
Hello PF. I'm currently tackling a problem at work that I could use some input on.
I am trying to gather data regarding the force applied by a swelling material against the ID of a pipe. The purpose is to determine how the force increases with swell before leveling off, as well as to see how...
I understand the right hand rule and the equition, but why is the direction of the torque perpendicular to the force on the counter clockwise side of the force and crossing the rotational point?
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...
Force" F"is applied on M1 .Although force applied is not directly on M2,but it will also experience this force" F" via M1,right?
But I don't think it is correct.Because it implies that no matter how big the force on M1,the net force on M1 will always remain zero.And there will be unbalanced...
Hello,
I need to calculate the force applied within a clutch pack by an expanding disk. Can you guys tell me if there is anyway to do this? I am working to find the torque capacity of a centrifugal clutch using the equation:
Torque Capacity = 2/3 * COF * n * F * Radius Gyration
where COF =...
Hi,
I am going to try and explain this as best I can. I have a drum submerged in water (200ltr drum) filled with +- 150ltr of air. This is attached to a chain that goes around a sprocket at the bottom of the tank and the sprocket is mounted to a shaft that goes out of my tank. How do I calculate...
Homework Statement
Q: A boy falls with the acceleration 4g in a free fall until he hits a net. His mass is 78kg. You can ignore other forces. With what force does he influence the net?
Homework Equations
F=m*a
The Attempt at a Solution
I use the formula F=m*a which gives med...
Today in class we learned about how if a force F is applied to a dumbbell on its center of mass and then separately applied to the edge where it gets its maximum torque, the dumbbell will have the same CM velocity after. It makes sense when you think about it in terms of momentum. F times T...
Homework Statement
A box of mass 72 kg is at rest on a horizontal frictionless surface. A constant horizontal force of magnitude F then acts on the box, accelerating it to the right. You observe that it takes the box 3.4 seconds to travel 13 meters. What is the magnitude of the force F?
m =...
Homework Statement
A spring is compressed from both ends by 100 Newtons and the spring constant is given as 1000N/m. What is the net compression distance/displacement (x)?
Homework Equations
F=-k*change(x)
The Attempt at a Solution
Initially, I thought that the net displacement would...
Homework Statement
The problem is described and drawn here:
https://drive.google.com/file/d/0B-HFS9bOMNAcMjNacXlha0Z6cVk/edit?usp=sharing
Edit: The picture seems not to be showing up, so the address is: https://drive.google.com/file/d/0B-HFS9bOMNAcMjNacXlha0Z6cVk/edit?usp=sharing...
Hello all new to the forums but I have a question. I need to find out the force that holds two pressed objects together. For example I have a piece with a diameter of 1.000 in and another piece (the shaft) with has a diameter of 1.001. The shaft is inserted .25in into the 1.000in opening. The...
Homework Statement
This is a general question about Statics. I was not able to find a specific question that includes this situation.
I have a right triangle ABC with two (or three) members. Member AC is diagonal with a pin support (prevents translation) at C. Member AB is horizontal with...
A force is applied to m1 connected to m2 by a "massless" cord. where m2>m1.
the acceleration, a, is a = F/m1+m2
By decomposing the system into A and B where A refers to the tension on m1 upon having the force applied onto m2, the tension TA is to the positive x-direction.
However, in...
Homework Statement
A net force along the x-axis that has x-component Fx=−12.0N+(0.300N/m2)x2 is applied to a 3.20kg object that is initially at the origin and moving in the -x-direction with a speed of 8.60m/s
What is the speed of the object when it reaches the point x = 9.00m ...
To experiment with conservation of linear momentum I did lab where a jet of water is shot at a flat plate and a hemispherical cup. After simplification the final equation for the theoretical force came out to be
F_t= \dot{m}V(1-cos \beta)
where \dot{m} is the mass flow rate of water and V...
I am working on a project at my University. It's extra-curricular and not homework related. At the end we will give a report on what we learned during the development. Our team is working on some ideas for a basic robotic climber, that climbs a cable (similar to a seatbelt).
What we decided...
Homework Statement
Suppose a wheel with radius R is resting on a non-inclined surface. A torque \tau is applied to the wheel center. In an attempt to prevent wheel from spinning, the ground applies a static friction force to the wheel at the contact point (parallel to the surface), then the...
Homework Statement
A force of 25 N is applied on the pulley. M1 = 1.5 kg, M2 = 2.5 kg, light frictionless strings and pulley.
a) What is the tension in the strings?
b) What is the acceleration of the masses?
c) What is the minimum Force to apply on the pulley so that M2 comes off the...
A force is applied to a box that is initially at rest on an inclined surface. The incline is at an angle θ=20.0° above horizontal. The mass is m=36kg and the vertical force is Fapp= 48N. Between the box and the inclined surface the coefficient of static friction, μs=.240 and a coefficient of...
The coefficient of static friction between the crate m1=3.00kg and the incline with θ=35° shown in the figure below is .300. What minimum force F must be applied to the crate perpendicular to the incline to prevent the crate from sliding down the incline?
mgsinθ
μsmgcosθ
f=ma
I don't quite get...
Homework Statement
Scroll down for pic related
Determine the tension
in the cable P that will give the 50 kg block a steady accelerationof 2.0 m/s^2 up the incline.
Homework Equations
Where am I going wrong?
The Attempt at a Solution
Let Fa=force applied
I calculated the...
Hello,
If I have a shaft that has a section area of .0562 in. sq. and a material yield strength of 60KSI.
And I will have the force applied at the top of the shaft pushing down.
The shaft will be in a cantilever configuration where the force will be applied .125" from the base of the shaft...
Homework Statement
The horizontal surface on which the block slides is frictionless. If F = 20 N and M = 5.0 kg, what is the magnitude of the resulting acceleration of the block? The force is applied 30° to the horizontal.
Homework Equations
F=ma
The Attempt at a Solution
I began...
Hi all. I am marking GCSE paper that I did myself. There is 1 problem that I do not seems to understand. Please help me. Thank you very much.
Homework Statement
Daniel pulls a 3kg box up a slope from rest as shown (Attached)
Given that the average friction of a slope is 2N and the speed at...
Homework Statement
A car is moving at an acceleration such that a 5kg block in the back of the remains still on a ramp at 35*. The ramp is frictionless, whereas the coefficient of friction between the truck and the road is μ=0.1. If the truck weighs 12000kg, what is the force the trucks...
Homework Statement
2kg block moving across a flat surface with a friciton coefficient of .2
a. If 10N force applied what is acceleration
b How fast will the block move if the force is applied for 5seonds
c. how far will the block have traveled after 5 seconds
Homework Equations...
Homework Statement
A sling shot can launch a 50gram rock at a speed of 24m/s if it is stretched .4meters before release. Find the average force applied to the rock
Homework Equations
Spring force = 1/2*k*x^2
1/2kx^2 = 1/2mv^2
The Attempt at a Solution
tried to solve for K...