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# Physics Finals Help

### Need to study for Physics? Here are some questions to help you out!!!

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

Chapter 1 | Motion |

When is an object in motion? | An object is in motion when its distance from another object is changing. |

What is a reference point? | A reference point is a place or object used for comparison to determine if something is in motion. |

What is the International System of Units? | Also known as SI, or system international, this is a system of measurements which scientists use all around the world to communicate information clearly. |

What is the main unit of length in SI? | The main unit of length in SI is the meter, which is a bit longer than a yard. |

What is speed? | Speed's the distance an object travels in a certain amount of time. |

How do you calculate speed? | Speed = Distance/Time. The meaurement is meters per second or m/s |

When is an object at a constant speed? | An object is at a constant speed if the speed of that object does not change. |

How do you find an objects average speed? | To find an objects average speed you divide the total distance of the trip, and divide it by the total time to travel that distance. |

When do you know the velocity of an object? | When you know the speed and direction of an object's motion, you will know its velocity. Basically, velocity is speed in a certain direction. |

What a slope of a graph? | A slope is the steepness or slant of a line on a graph. |

How do you calculate slope? | slope = rise/run |

What is acceleration? | Acceleration is the rate at which velocity changes. Because velocity = speed in certain direction, acceleration refers to 1) increasing speed, 2) decreasing speed, or 3) changing direction |

How do you calculate acceleration? | Acceleration = Final Velocity - Initial Velocity, divided by Time |

What is a linear relationship? | If points on a graphed line rise the same amount each time, then the line has a linear relationship. |

What is a nonlinear relationship? | If a line on a graph doesn't rise the same amount each time, then it has a nonlinear relationship. |

Chapter 2 | Forces |

What is a force? | A force is a push or pull. |

What is a net force? | The net force is the overall amount of forces after all of the forces are added together. |

What is an unbalanced force? | An unbalanced force is a force that will change an objects motion (cause it to start moving, stop moving, or change the objects motion) |

What is a balanced force? | Ballanced forces are equal forces acting on one object in opposite directions. Balanced forces will not change an objects motion. |

What is inertia? | Inertia is the tendency of an object to resist change in its motion. |

What is Newton's first law of motion? | Newton's first law of motion says that an object at rest will stay at rest, and an object in motion will stay in motion, unless acted upon my an unbalanced force. |

What is mass? | Mass is the amount of matter in an object. |

What is Newton's second law of motion? | Newton's second law of motion says that the net force on an object is equal to the product of its accelration and its mass. (Force = Mass x Acceleration) |

What is friction? | Friction a force that one surface exerts on another when the two rub against each other. The strength of the force of friction depends on two factors: the types of surfaces involved and how hard the surfaces push together. |

What are the three types of friction? | The three types of friction are: 1) sliding friction, surfaces sliding on each other 2) rolling friction, objects that roll on each other and 3) fluid friction, objects that moves through a liquid or gas.. |

What is gravity? | Gravity is the force that pulls objects together. |

When is an object in its freefall? | An object is in its freefall when the only force on a falling object is gravity. |

What is a projectile? | A projectile is an object that is thrown. |

What is air resistance? | Air resistance is a type of fluid friction that objects experience when they fall through the air. |

When does an object reach its terminal velocity? | An object reaches its terminal velocity when it reaches its greatest velocity. |

What is weight? | The force of gravity on a person or object at the surface of a planet. |

How do you calculate weight? | Weight = Mass x Acceleration due to gravity (9.8 m/s squared) |

What is Newton's third law of motion? | Newton's third law of motion says if one object exerrts a force on an object, the second object exerts a force of equal magnitude in the opposite direction of the first object. |

What is momentum? | Momentum is the quantity of motion. Momentum is the product of an objects mass and its velocity. Momentum = Mass x Velocity. The unit of measurement for momentum is kilogram-meters per second (kg x m/s) |

What does the law of conservation of momentum say? | The law of the conservation of momentum says that the total momenum of the objects that interact does not change unless an outside force acts upon it. |

That is the end of Chapter 2 Take a break....there is more to come!!! | INTERMISSION |

Chapter 3 | Forces in fluid |

What is pressure? | Pressure is the force that is exerted on a surface, divided by the total area over which the force is exerted. Pressure = Force/Area. |

What is the unit of measurement for pressure? | The unit of measurement for pressure is called a pascal, Pa, which equals 1 Newton meter squared (1N/m squared) |

What is a fluid? | A fluid is a substance that can easily flow. Because it can flow easily, it can easily take different shapes. |

What does Pascals principle state? | Pascals principle says that when a force is applied to a convined fluid, the pressure is applied equally to all parts of the fluid. |

What do hydraulic systems do? | Hydraulic systems multiplies a force by applying the force to a small surface area. The increase in pressure is then transmitted to another part of a confined fluid, which pushes on a larger surface area. |

What is a buoyant force? | A buoyant force is a force that water exerts on a submerged object and acts in an upward direction against the force of gravity which makes the objects feel lighter. |

What does Archimedes' principle say? | Archimedes' principle says that the buoyant force on an object is equal to the weight of the fluid displaced by the object. |

What is density? | Density is the measurement of how much mass of a substance is contained in a unit of volume. |

An object that is more dense than the fluid it is in will... | Sink |

An object that is less dense than the fluid it is in will... | Float |

An object that has equal density to the water that it is in will... | Suspend in the water |

What does Bernoulli's principle say? | Bernoulli's principle says that pressure exerted by a moving stream of fluid is less than the pressuer of the surrounding fluid. |

Chapter 4 | Work and Machines |

What is work? | In science, you do work on an object when you exert a force on the object that causes the object |

In order to do work on an object, you must.... | 1) make the object move some distance, 2) have the force you exert be in the same direction of the objects motion. |

How do you calculate work? | Work = Force x Distance. The unit of measurement for work is a joule, or J, which is a Newton meter, Nm |

How does a machine make work easier? | A machine makes work easier by changing the amount of force you exert, the distance which you exert your force, or the direction in which you exert your force. |

What is an input force? | An input force is the force you exert onto a machine. |

What is an output force? | An output force is the force exerted by the machine. |

What is a machines mechanical advantage? | A machine's mechanical advantage is the number of times a force exerted on a machine is multiplied by the machine. |

What is the formula to find the mechanical advantage of a machine? | Mechanical advantage = Output force/Input force. |

What is a machine's efficiency? | The efficiency of a machine compares the output work to the input work. It is expressed as a percent. |

What is the formula to find efficiency? | Efficiency = Output force/Input force x 100% |

What is an actual mechanical advantage? | The actual mechanical advantage of a machine is the mechanical advantage that a machine provides in a real situation. |

What is an ideal mechanical advantage of a machine? | The ideal mechanical advantage of a machine is the mechanical advantage without friction. The more efficient a machine is, the closer the actual mechanical advantage is to the ideal mechanical advantage. |

What are the six basic types of simple machines? | The six types of simple machines are: 1) the inclined plane, 2) the wedge, 3) the screw, 4) the lever, 5) the wheel and axle, 6) the pulley. |

What is an inclined plane? | An inclined plane is a flat slanted surface. (ex. ramp.) |

How do you find the ideal mechanical advantage of an inclined plane? | To find the mechanical advantage of an inclined plane, divide the length of the incline by its height. |

What is a wedge? | A wedge is a device that is thick at one end and tapers to a thin edge at the other end. (ex. axe) |

What is a screw? | A screw can be thought of as an inclined plane wrapped around a cylinder. (ex. twisty slide) |

What is a lever? | A lever is a rigid bar that is free to pivot or rotate, about a fixed point. (ex. seesaw) |

What is a fulcrum? | A fulcrum is the fixed point that a lever pivots around. |

How do you find the ideal mechanical advantage of the lever? | To find the ideal mechanical advantage of a lever, you divde the distance from the fulcrum to input force, by the distance from the fulcrum to the output force. |

What is a wheel and axle? | A wheel and axle is a simple machine made of two circular or cylindrical objects that rae fastened together and that rotate abouta common axis. (ex. car) |

How do you find the ideal mechanical advantage of a wheel and axle? | To find the ideal mechanical advantage of a wheel and axle, you divide the radius of the wheel, by the radius of the axle. |

What is a pulley? | A pulley is a grooved wheel with a rope, or chain, or steel cable, wrapped around it. |

How do you find the mechanical advantage of a pulley? | The ideal mechanical advantage of a pulley system is equal to the number of sections of the rope that support the object. (ex. flagpole). |

What is a compound machine? | A compound machine is a machine that has 2 or more simple machiens in it. (ex. mechanical pencil sharpener). |

What are gears? | A gear is 2 or more wheels locked together by interlocking teeth. |

What are tendons? | Tendons are the tissue which attach your muscles to your bones. |

Chapter 5 | Energy and Power |

What is energy? | Energy is the ability to do work or cause change. |

What are the 2 types of energy? | The two types of energy are: 1) kinetic energy, and 2) potential energy. |

What is kinetic energy? | Kinetic energy is the energy of motion. |

How do you calculate kinetic energy? | Kinetic Energy = Mass x Velocity squared, divided by 2. |

What is potential energy? | Potential energy is energy that is stored and held in readiness. |

What types of potential energy are there? | 1) Elastic potential energy, potential energy associated with objects that can be stretched or compressed., and 2) gravitational potential energy, energy that depends on height. |

How do you calculate gravitational potential enrgy | Gravitational potential energy = Weight x Height. |

What is the unit of measurement for energy? | The unit of measurement for energy is a joule, J |

What is the calculation for gravitational potential energy if you don't know the weight? | Gravitational potential energy = Mass x Gravitational acceleration (9.8 m/s) x Height. |

What are the 6 major forms of energy? | 1) Mechanical Energy, 2) Thermal Energy, 3) Chemical Energy, 4) Electrical Energy, 5) Electromagnetic Energy, 6) Nuclear Energy. |

What does the law of conservation of energy say? | The law of conservation of energy says that when one form of energy is converted to another, no energy is destroyed in the process. |

What is power? | Power is the rate at which work is done or the amount of work is done in a unit of time. |

How do you calculate Power? | Power = Force x Distance divided by Time. The unit of measurement for power is 1 watt, which is equal to 1 Joule per second. |