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# PhysicsFinal2012

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

What is the area of physics that studies motion and its causes? | Quantum Mechanics |

A baker makes a loaf of bread. Identify the area of physics that this involves. | Thermodynamics |

According to the scientific method, how does a physicist formulate and objectively test hypotheses? | By experiments |

Why do physicists use models? | To explain the basic features of complex phenomena. |

What two dimensions, in addiction to mass, are commonly used by physicists to derive additional measurements? | Length & Time |

The symbol mm represents a | millimeter. |

The symbols for units of length in order from smallest to largest are | mm, cm, m, and km. |

The SI base unit used to measure mass is the | kilogram. |

The SI base unit for time is | 1 second. |

The most appropriate SI unit for measuring the length of an automobile is the | meter. |

If some measurements agree closely with each other but differ widely from the actual value, these measurements are | precise but not accurate. |

Poor precision in scientific measurements may arise from | human error. |

In a gam of horseshoes, one horseshoe lands on the post. Four horseshoes land nowhere near the post. The one horseshoe on the post was thrown A. Accurately B. Precisely. C. both accurately and precisely. D. neither accurately nor precisely. | A. Accurately |

The Greek letter delta, (triangle), indicates a | difference or change. |

What are the basic SI units? | meters, kilograms, seconds |

What is the speed of an object at rest? | 0.0 m/s |

What is the expression for average velocity? | Vavg = delta x / delta t |

In addition to displacement, which of the following must be used for a more complete description of the average velocity of an object? | delta t |

Acceleration is | the rate of change of velocity. |

What is the expression for acceleration? | a = delta v / delta t |

When velocity is positive and acceleration is negative, what happens to the object's motion? | The object slows down. |

Acceleration due to gravity is also called | free-fall acceleration. |

The baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball's path does it experience zero velocity and zero acceleration at the same time? | the ball never experiences zero acceleration during its flight |

When there is no air resistance, objects of different masses | fall with equal accelerations with similar displacements. |

Which would hit the ground first if dropped from the same height in a vacuum, a feather or a metal bolt? | They would hit the ground at the same time. |

What is free fall? | Acceleration due to gravity. |

Why is the direction of free-fall acceleration negative? | There is always the force of gravity pulling downward on the object. "What goes up must come down." |

Tangent is | opposite/adjacent |

Sine is | opposite/hypotenuse |

Cosine is | adjacent/hypotenuse |

What quantity has a magnitude and direction? | Vector Quantity (ex: velocity, acceleration, force) |

What quantity can be completely described by its magnitude only? | Scalar Quantity (ex: speed, velocity, mass, time) |

What is the vector representing the sum of 2 or more vectors? | Resultant |

What type of motion is two-dimensional motion? | Projectile motion |

The projections of a vector along the axes of a coordinate system are the | components of a vector. |

What causes changes in the velocity of objects? | Force |

What three things can force do? | 1. Can stop a moving object 2. Can cause a stationary object to move 3. Can change the direction of a moving object |

What is the result from physical contact with surfaces? | Contact forces (ex: pushing, friction, etc.) |

What are forces that act across space? | Field forces (ex: gravity, magnetism, electricity) |

What describe forces acting on or affecting the motion of an object? | Free Body Diagrams |

Who made the Newton? | Sir Isaac Newton |

An object at rest remains at rest, and an object in motion continues in motion with constant velocity unless the object experiences a "Net external force" | Newton's First Law |

The tendency not to change its state of motion | Inertia |

Objects are either at rest or moving with a constant velocity | Equilibrium |

Poop eating | Coprophagy |

The acceleration of an object is directly proportional to the net external force acting on the object and inversely proportional to the object's mass | Newton's Second Law |

For every action, there is an equal and opposite reaction | Newton's Third Law |

The forces two objects mutually exert on each other when they interact | Action-Reaction pair |

The magnitude of the gravitational force exerted on an object | Weight |

A force exerted by one object on another in a direction perpendicular to the surface of contact | Normal Force (Fn) |

Opposes forces applied to an object | Friction |

The frictional force that opposes motion between two surfaces in contact with one another and at rest relative to each other | Static Friction (Fs) |

Point at which Fs is overcome | Fsmax |

Frictional force between two objects in contact with each other and moving relative to each other | Kinetic Friction (Fk) |

Fapp - Fk | Fnet |

Proportional to the normal force and depends on the surface in contact | Friction |

Ratio of friction to the normal force | Coefficient of friction |

Is a form of friction (that we have thus far ignored) | Air resistance |

Air resistance | Fr |

As velocity increases, Fr | increases. |