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Module 4 Lesson 1.13 Lesson 1.13 |
MODULE 4 - DEFINITIONS
Momentum: The product of mass and velocity Impulse: The product of force and time. Elastic Collision: An interaction between objects in which the total energy of the objects remains constant. Inelastic Collision: A collision in which some of the kinetic energy of the interacting objects is transformed into another form. Equilibrium: When the net or resultant force acting on an object is zero, the object is not accelerating and it is said to be in equilibrium. It is possible for an object in equilibrium to be at rest or to be moving or turning at a constant rate. It can not be accelerating. Stable equilibrium: An object is in stable equilibrium if it returns to its original position when it is moved a small distance from its equilibrium position. Unstable equilibrium: An object is in unstable equilibrium if moving it a small distance from its equilibrium position causes it to move further from its equilibrium position. Center of mass: A point at the center of an object’s distribution of mass. The mass of the body can often be regarded as being concentrated at that point. Center of gravity: A point at the center of an object’s distribution of weight. Unless the object is very large, the center of mass is located at the same point ass the center of gravity. Toppling: This occurs if a vertical line through the center of mass does not pass through the base of the object. Buoyancy: The result of an upward force on an object immersed in a fluid. Center of buoyancy: The point at which the buoyant forces on an object could be considered as being concentrated. It is located at the center of mass of the body of fluid displaced by the immersed object. Machine: A device that changes the magnitude or direction of a force. Lever: A simple machine consisting of a rigid object that is pivoted about an axis or fulcrum. Fulcrum: The point at which a lever is pivoted. Pulley: A wheel used to change the direction of the tension in a rope, cable or string. Mechanical Advantage: The mechanical advantage of a machine is the ratio of the force produced by the machine to the force applied to the machine. Efficiency: The ratio of the output of useful energy from a machine to the energy input. Velocity: Displacement (in a particular direction) in a specified period of time. Torque: A measure
of the ability of a force to cause rotation. Torque is
the product of the distance from the center of rotation
and the magnitude of the force acting perpendicular to
the line from the point of rotation to the point at which
the force is applied. Moment: Torques are
sometimes referred to as moments or turning moments. Tangential Force: The
force acting at a tangent to the circle through which it
tends to move while causing rotation. This force acts
perpendicularly to the line from the point of rotation to
the point at which the force is applied. Rotational Velocity: Rotational
speed around a particular axis. Angular Momentum: The
product of rotational inertia (or moment of inertia) and
the rotational velocity. Rotational Inertia: The
tendency of a rotating object to oppose a change in its
state of rotation Revolution: Movement
of an object around an axis located outside of the object. Rotation: Movement or spinning of an object around an axis located inside the object.
Momentum = mass x velocity
Impulse = force x time
Impulse = change in momentum
Work = force x distance
Power = work / time
. . . . . . . . .
. . . . . . . . . . . . .. .Output
force .
. . .Distance moved
by input force
. . . . . . . . .
. . . Useful work
output
Circumference of a circle = p d or 2p r Where: d = diameter r = radius
Torque = tangential force x distance from center of rotation
Angular momentum = m v r Where: m = mass (kg) v = tangential velocity (speed) (m/s) r = radius – average distance of mass from center of rotation.
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