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# MCAT Physics Ch 1

### MCAT Physics

Question | Answer |
---|---|

Vector | physical quantity that has both magnitude and direction. Ex: Displacement, velocity, accel., force |

Scalar | Quantity without direction. Ex: Speed, coeff. of friction |

Note about multiplying a vector by a scalar | This changes the magnitude and may reverse the direction |

Dot Product | Product of the vectors' magnitudes and the cosine of the angle between them. |

Note About Multiplying Two Vectors Using The Dot Product | This results in a scalar quantity |

Cross Product | Product of the vectors' magnitudes and the sin of the angle between them |

Note About Multiplying Two Vectors Using The Cross Product | This results in a vector quantity |

Displacement | Vector rep. of change in position |

Distance | Scalar quantity that reflects the path traveled. |

Velocity | Vector representation of the change in displacement with respect to time. |

Average Velocity | Total displacement divided by the total time. |

Instantaneous Velocity | Limit of the change in displacement over time as the change in time approaches zero. |

Instantaneous Speed | Mag. of instantaneous velocity vector. |

Force | Push or pull that has the potential to result in an accel. |

Gravity | Attractive force between two objects as a result of their masses |

Friction | A force that opposses motino as a function of electrostatic interactions at the surface between two objects |

Static friction | Friction between two objects that are not in motion relative to one another. |

Kinetic Friction | Friction between two objects that are in motion relative to each other |

Coefficient of friction | Depends on the two materials in contact. Coefficient of static friction is always higher than the coefficient of kinetic friction. |

Mass | Measure of inertia of an object (amount of material) |

Weight | Force experienced by a given mass due to grav. accel to Earth |

Acceleration | Vector rep. of change in velocity over time. Avg or inst. accel can be considered similar to velocity |

Newton's First Law / Law Of Inertia | An object will remain at rest or move with a constant velocity if there is not net force on the object |

Newton's Second Law | Any accel. is the result of the sum of the forces acting on the object and its mass. |

Newton's Third Law | Any two objects interacting with one another experience equal and opp. forces as a result of their interaction. |

Linear Motion | Free fall and motion in which vel. and accel. vectors are parallel or antiparallel |

Projectile Motion | Has an x and y component. Without air resistance, only force acting on an object is gravity. |

Inclined Plane | Ex of 2D movement. |

Circular Motion | motion with radial and tangential dimensions |

Uniform Circular Motion | Centripetal force that points radially inward. NOTE: Inst. Vel. Vector always points tangentially |

Free Body Diagrams | Rep's of forces acting on an object that are used for equilibrium and dynamics problems. |

Translational Equilibrium | Equilibrium of an object without any net forces acting upon it. The object has a constant velocity, and may or may not be in rotational equilibrium. |

Rotational Equilibrium | Equilibrium of an object without any torques acting upon it. An object with rotational equilibrium has a constant angular velocity which is usually zero. |

Component Vectors | X = vcos(angle), Y = vsin(angle) |

Pythagorean Theorem | X^2 + Y^2 = V^2 OR V = Sqr (X^2 + Y^2) |

Determination of Direction From Component Vectors | Angle = Tan-1 Y/X |

Dot Product | A*B = |A|*|B| * cos(angle) |

Cross Product | AXB = |A| |B| * sin(angle) |

Instantaneous Velocity | v = lim t --> 0 Delta x / Delta t |

Avg Velocity | V = Del. x / Del. t |

Universal Grav Equation | Fg = Gm1m2 / r^2 |

Static Friction | 0 <= fs <= usN |

Kinetic Friction | fk = uKN |

Force Of Gravity (weight on Earth) | Fg = mg |

Center of mass | x = m1x1 + m2x2 ... / m1 + m2 ... |

Avg Acceleration | a = Del. v / Del. t |

Instantaneous Accel | a = lim (t-->0) Del. v / Del. t |

Newton's First Law | Fnet = ma = 0 |

Newton's Second Law | Fnet = ma |

Newton's Third Law | FAB = -FBA |

Kinematics (no displacement) | v = v0 + at |

Kinematics (no final velocity) | x = v0t + at^2/2 |

Kinematics (no time) | v^2 = v0^2 + 2ax |

Kinematics (no accel) | x = vt |

Components of Gravity On An Inclined Plane | Fg para. = mg*sin(angle), Fg perp. = mg*cos(angle) |

Centripetal Force | Fc = mv^2 / r |

Torque | T = r x F = rF * sin(angle) |