Mechanics

Vocabulary

• Acceleration

  • $a$ , Is the time rate of change of velocity

• Centripetal acceleration

  • An object moving uniformly in circular path always has centripetal acceleration which is an acceleration directed toward the center of the circle

• Centripetal force

  • $F_{c}$ , The force needed to keep an object moving in a circular path

• Closed system

  • A group of objects, not acted upon by any external force

• Coefficient of friction

  • Is the ratio of the frictional force to the normal force, and thus has no unit

• Displacement

  • The change in position of an object described by a vector that begins at the initial position of the object & ends at the final position

• Distance

  • The total length of a path that an object travels

• Equilibrium

  • If the net force acting on an object is zero it is in equilibrium, an object at rest is said to be in static equilibrium

• Free fall

  • The ideal falling motion of an object acted upon only by the force of gravity

• Free-Body diagram

  • A sketch or scale drawing, that shows all the forces acting concurrently on an object

• Friction

  • The force that opposes the relative motion of two objects in contact

• Gravitational field

  • A region in space where a test particle would experience a gravitational force

• Gravitational field strength

  • At any point in a gravitational field, gravitational field strength, g equals the force per unit mass at that point

• Gravitational force

  • The attractive force that one object exerts on another object due to their masses

• Gravity

  • Is the force between the mass of Earth and the mass of any object in the vicinity of Earth

• Horizontal component

  • Is a component parallel to the horizon

• Impulse

  • The product of the net force acting on an object and the time during which the force acts

• Inertia

  • Is the resistance of an object to a change in its motion

• Instantaneous velocity

  • Is the velocity of an object at any particular instant in time

• Kinetic friction

  • Friction between objects in contact when they are in motion

• Law of Conservation of Momentum

  • The total momentum of the objects in a closed system is constant

• Linear motion

  • Refers to an object’s change of position along a straight line

• Mechanics

  • The branch of physics that deals with forces and the way they produce and change motion

• Momentum

  • The product of an object’s mass and velocity is a vector quantity

• Net force

  • The vector sum of the concurrent forces acting on an object

• Newton

  • One newton is equal to the force that imparts an acceleration of one meter per second² to a one kilogram mass

• Normal force

  • Is the force pressing the two contacting surfaces together

• Pendulum

  • Consists of a mass, $m$ attached to a string of negligible mass

• Period (of a pendulum)

  • The time required for the displaced pendulum to complete one cycle of motion, $T$

• Resolution of Forces

  • The process of determining the magnitude and direction of the components of a force

• Resultant

  • The single force that is equivalent to the combined effect of these concurrent forces

• Speed

  • $v$ , of an object is the distance that the object moves in a unit of time

• Static friction

  • The force that opposes the start of motion

• Unbalanced force

  • Is a nonzero net force acting on an object

• Uniform circular motion

  • If the applied force has a constant magnitude and always acts perpendicular to the direction of the object’s velocity, the object moves in a circular path at constant speed

• Uniform motion

  • If the object’s speed is constant during the entire time interval,$\overline{v}$ is it’s constant speed the object is in uniform motion

• Vacuum

  • Is a space in which there is no matter

• Vector component

  • The vector component of a force vector F are the concurrent forces whose vector sum is F

• Velocity

  • Is the time rate of change of the displacement of an object

• Vertical component

  • Is a component at right angles to the horizon

• Weight

  • The gravitational force with which a planet attracts a mass

Newton’s Three Laws of Motion

1.     According to Newton’s first law, an object maintains a state of

Formulas