The product of average force and the time it is exerted is called the impulse of force. From Newton's second law [pic]
the impulse of force can be extracted and found to be equal to the change in momentum of an object provided the mass is constant: |[pic] |Calculation |

The main utility of the concept is in the study of the average impact force during collisions. For collisions, the mass and change in velocity are often readily measured, but the force during the collision is not. If the time of collision can be measured, then the average force of impact can be calculated.

Examples Involving Impulsive Force

• Playing football
• Playing badminton
• Playing tennis
• Playing golf
• Playing baseball

Impulsive force is produced during collision according to the Newton's Second Law. If time of impact is reduced, the greater the impulsive force produced causing severe damage to the car.

Long Jump

[pic]
1. The long jump pit is filled with sand to increase the reaction time when atlete land on it. 2. This is to reduce the impulsive force acts on the leg of the atlete because impulsive force is inversely proportional to the reaction time. High Jump

[pic]
• During a high jump, a high jumper will land on a thick, soft mattress after the jump. • This is to increase the reaction time and hence reduces the impulsive force acting on the high jumper. Jumping

A jumper bends his/her leg during landing. This is to increase the reaction time and hence reduce the impact of impulsive force acting on the leg of the jumper. Crumble Zone
The crumple zone increases the reaction time of collision during an accident. This causes the impulsive force to be reduced and hence reduces the risk of injuries.

Seat Belt
[pic]
Prevent the driver and passengers from being flung forward or thrown out of the car during an emergency break.

...Definition of Force
A force is a push or pull upon an object resulting from the object's interaction with another object. Whenever there is an interaction between two objects, there is a force upon each of the objects. When the interaction ceases, the two objects no longer experience the force. Forces onlyexist as a result of an interaction.
Velocity, Acceleration, Momentum, and Impulse
Velocity, in physics, is a vector quantity (it has both magnitude and direction), and is the time rate of change of position (of an object). However, quite often when you read ‘velocity’, what is meant is speed, the magnitude of the velocity vector (speed is a scalar quantity, it has only magnitude). For example: escape velocity (the minimum speed an object needs to escape from a planet, say); note that this can be easily turned into a velocity, by adding ‘in the direction radially out from the center of the planet’, and that this direction is sometimes implied (if not actually stated).
Velocity is a vector measurement of the rate and direction of motion or, in other terms, the rate and direction of the change in the position of an object. The scalar (absolute value) magnitude of the velocity vector is the speed of the motion. In calculus terms, velocity is the first derivative of position with respect to time.
The most common way to calculate the constant velocity of an object moving in a straight line is with...

...Force & Motion
Isaac Newton – English physicist & mathematician.
Newton’s First Law of Motion(Law of Inertia):
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalance force.
An object at rest tends to remain at rest. An object in motion tends to move at a constant speed in a straight line unless acted upon by an unbalanced externalforce.
Newton’s Second Law of Motion(Law of Acceleration):
An object’s acceleration is directly proportional to the net force acting on it and is inversely proportional to the object’s mass.
Newton’s Third Law of Motion(Law of Interaction):
For every action, there is always an equal and opposite reaction.
Force is any interaction which tends to change the motion of an object. It can also be described by intuitive concepts such as a push or pull.
Unbalanced Forces
An object is said to be acted upon by an unbalanced force only when there is an individual force that is not being balanced by a force of equal magnitude and in the opposite direction.
Direct proportion- means that when one factor increases, the other factor also increases and vice versa.
Inverse proportion- means that when one factor increases, the other factor decreases.
Acceleration- increase in the rate or speed of something....

...Physics notes
Force is an agent which produces or tends to produce motion in an object, stops or tends to stop , motion of an object
Newton's 1st law of motion:
If an object is at rest, will remain at rest until or unless an external force act on it. If an object is in motion , it continues its motion until or unless an external force act on it
Newton's 1st law of motion is also called first law of inertia.
Inertia:
The tendency of an object to resist any change in its state of motion or rest is called inertia.
Inertia is the measure of mass in an object.
Heavier object are difficult to bring in motion or in rest because they've greater inertia.
Newton's 2nd law of motion:
Force produces acceleration in an object in its own direction. The acceleration is directly proportional to the force and inversely proportional of the mass of the object.
Resultant force is unbalanced force.
F=ma , where F is the resultant force.
Q: the mass of a boy n his bicycle is 30kg, wants to accelerate at 1.5per sec square if the opposing force is acting on both is 40N
Find the force needed for this acceleration.
Q2: a car of weight 50,000N is moving with a uniform speed of 20meters per sec
The opposing force is acting on the car is 600N
Find:
a: the force applied by the engine
b: if the engine...

...awe of the fidelity of the principles and laws that allow me to escape the grips of gravity and observe the aerodynamics of flight.
Although, there are many concepts when it comes to aerodynamics, I’m going to discuss the four major ones today. Lift, weight, thrust, and drag. During flight, there is a constant relationship between these forces. Lift is the upward force created by the effect of airflow as it passes over and under the wing. The airplane is supported in flight by lift. Weight, which opposes lift, is caused by the downward pull of gravity. Thrust is the forward force which propels the airplane through the air, which varies with the amount of engine power being used. Opposing thrust is drag, which is a backward, or retarding, force which limits the speed of the airplane. I’m also going to introduce Newton’s second law, which explains how an object will change velocity if it is pushed or pulled upon, Newton’s third law, which states that forces always come in equal and opposite pairs, as well as Bernoulli’s principle, which explains how the differences in pressure create lift.
Lift is the key aerodynamic force. It is the force that opposes weight. A plane that sits on a runway doesn't have any lift, but it does have weight. Bernoulli's principle also applies to lift in the following manner: Air passes over the top of a wing, which results in lower pressure,...

...* Constant speed = no acceleration = sum of all net forces is zero
* An object in orbit around the earth is not truly weightless
* Sitting half as far away from your class mate the gravitation force is four times as strong. (re2)
* Newton’s First Law- inertia an object that is not moving will remain at rest (ex: and apple hanging from a tree)
* The reason you head feels like it jerks back ward is when pulling away from a stop sign is due to Newtons first law
* If two forces that are identical in strength but exactly opposite in direction act on the same object that object will not necessarily be motionless
* When drawing a FBD, the net force must not be included
* 2 people pushing an object across a frictionless surface will result in twice the acceleration than if only one was pushing. Assume the object slides in both cases and both people push with same force (true)
*
Types of forces:
* Dynamics: the study of motion
* No movement forces are balanced
* Applied Force: a force that results when one object makes contact with another (pushes or pulls it)
* Tension: a pulling force, with a rope/ string
* Normal force: only when in contact with something ie. The ground. Points away from surface
* Friction: opposes the sliding of two surfaces cross one...

...Force vs. Area
Connor Blackmon
Chemistry I H, 1st Period
Mrs. Kris Clements
October 18, 2012
Problem
Will a balloon pop if it is places on a bed of nails and pressure is applied?
Hypothesis
If a balloon is placed on a bed of nails and a force is applied, then the balloon will burst.
Variables
Independent variable- Force applied to the balloon and number of nails
Dependent variable- Does the balloon burst?
Materials
14 inch by 14 in by .75 in plywood board x2
196 nails
4 rods (14 inches tall)
Ruler
Pen
Drill
10 latex and 10 rubber balloons
Weights (1 lb, 5 lbs, 10 lbs; multiple of each weight)
Procedures:
Assembling the Board:
Using a pen and ruler, every one inch make a mark on one of the boards, these marks should be parallel to each other
use a drill to place a nail at each one of the points made on the board, all nails will be used
On the four corners drill a hole for a 14 inch rod facing the same way as the nails
Using the drill again, make four holes in the corners of the other plywood board for the rods to slide through
Experiment Procedures:
Inflate the rubber balloons to 11 inches in diameter, all balloons should be plus or minus .2 of an inch in diameter
Place rubber balloon on the middle of the bed of nails
Slide plywood board trough the rods to sandwich to balloon
Record if the balloon pops or not and weight applied to balloon...

...Force in effect when car brakes
A car of mass m=1200 kg is traveling at a speed of 50km/h. Suddenly the brakes are applied and the car is brought to a stop over a distance of 20m. Assuming constant breaking force find:
(1) the magnitude of the breaking force,
(2) the time required to stop.
(3) What will be the stopping distance if the initial speed is 100km/h?
Solution.
Most of problems from Dynamics can be seen as “two parts problem”, one involving kinematics and the other - dynamics. This is a consequence of Newton’s Second Law - Force is a product of mass and acceleration.
Acceleration by itself is a purely “kinematical” problem. When mass is involved, we go into Dynamics.
In our problem the following are given:
m = 1200 kg – mass of the car,
v1 = 50 km/h – initial speed in the first case,
D1 = 20m – stopping distance in the first case,
v2 = 100 km/h – initial speed in the second case.
We are suppose to find:
F = ? – magnitude of breaking force,
t = ? – the time required to stop,
D2 = ?<="" p="">
We write down formulas which involved the unknown quantities,
F = ma (1)
a = v1/t (2)
D1 = v1t –(1/2) a t2 (3)
Some explanations:
Formula (1) is simply Newton’s Second Law of Motion,
formula (2) – the speed decreases from v1 to 0 during time t. Assuming constant breaking force means constant acceleration (deceleration or acceleration...

...HYDROSTATIC FORCE (EXPERIMENT 1)
INTRODUCTION
The determination of force which are exerted by liquid which are at rest on surface immersed in liquids. From the study by hydrostatic, the following principles have been established :
a) There are no shear stress present when the fluid is not in motion.
b) The pressure exerted by a fluid under hydrostatic conditions. This pressure acts perpendicular to an immersed surface.
c) Hydrostatic pressure various linearly, increasing with an increase in depth.
OBJECTIVES
1. To determine the hydrostatic thrust on a plane surface partly immersed in water.
2. To determine the position of the line of action of the thrust.
3. To compare the position determined by experiment with the theoretical position .
4. To verify the formula for calculating hydrostatic thrust.
THEORY
When the quadrant is immersed in water it is possible to analyze the forces acting on the surfaces of the quadrant as follows:
The hydrostatic force at any point on the curved surface is normal to the surface and therefore resolves through the pivot point because this is located at the origin of the radii. Hydrostatic forces on the upper and lower curved surfaces therefore have no net effect – no torque to affect the equilibrium of the assembly because all of these forces pass through the pivot.
The forces on the sides of the...