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Physics Final
Physical Science, Physics Semester Final
Question | Answer |
---|---|
The distance traveled by an object divided by the time it takes to travel that distance is called | Average Speed |
What is the speed of an object at rest? | 0 km/h |
the difference between speed and velocity is that velocity includes | direction |
an airplane is flying at 635 km per hour at an altitude of 35,000 m. It is currently over Kansas and is approximately 16 minutes ahead of its scheduled arrival time. What is its velocity? | This cannot be determined without further information about its direction |
Acceleration is defined as the change in velocity divided by | time |
when the velocity of an object changes, it is acted upon by what? | a Force |
the combination of all the forces acting on an object is called the | net force |
if the net force acting on a stationary object is zero, then the object will | remain at rest |
a Tug-of-war that results in one team pulling the other across the line is an example of | unbalanced forces |
friction is defined as | force that opposes motion between two surfaces that are touching. |
A force is continuously applied to an object, causing it to accelerate. After a period of time, however, the object stops accelerating. What conclusion can be drawn? | The object is experiencing some kind of friction |
give an example of displacement | 3 blocks east |
Give an example of kinetic friction | friction between a car's windshield and the air as you drive into the wind |
how can the friction on a water slide be reduced | run a constant stream of water down the slide |
what is an example of balanced forces acting on an object | a leaf lying on the grass |
what are the factors required for calculating momentum | mass, speed, direction |
whenever an object is standing still, the values (s) that is/are always zero is/are | speed, velocity, and momentum |
a 10 kg dog chasing a rabbit north at 6 m/s has momentum of | 60 kgXm/s north |
weight is best described as | the downward force exerted on objects due to gravity |
the law that states that every object maintains constant velocity unless acted on by an unbalanced force is | Newton's First law of Motion |
the law that states that for every action force, there is an equal and opposite reaction force is | Newton's Third Law of Motion |
The law that states that the unbalanced force acting on an object equals the object's mass times its acceleration is | Newton's Second Law of motion |
The SI unit of force, named for the scientist who described the relationship between motion and force, is called the | Newton |
What is the unit used to measure acceleration in free fall | m/s2 (meters per second squared) |
how do you calculate weight | mass X gravity |
what is the reaction force when you place a cup on a table | the force of the table on the cup |
Earth pulls on the moon and holds the moon in its orbit. The moon pulls on Earth with an equal and opposite force. this is an example of what law | Newton's Third Law |
If two objects with different masses and traveling with different velocities collide, what law allows you to predict the motion of the objects after the collision? | the law of conservation of momentum |
When gravitational forces and air resistance equalize on an object that is falling toward Earth and the object stops accelerating. What is the velocity of an object called? | Terminal Velocity |
in the absence of air resistance, how would the acceleration of a 1.5 kg book and the acceleration of a 15 kg rock differ if the objects were dropped from the same height. | They would not differ; they would be the same |
what happens immediately after a skydiver opens her parachute? | Air resistance greatly increases |
what are the units of work? | Joules (J), Newtons X meters (Nm), Kilograms X square meters per second squared |
A man pushes a crate along a factory floor by exerting a force of 55 N. If the crate moves a distance of 4.0 m, how much work does the man perform? | 220N |
What are the units of power? | Watts, Horsepower, joules per secondl |
A machine is a device that | can multiply and change the direction of an input force |
what is the mechanical advantage of a single fixed pulley? | 1 |
what is an example of a wheel and axle? | a Screwdriver |
an inclined plane: | changes both the magnitude and the direction of the force |
what is included in the inclined plane family? | a wedge, a screw, and a ramp |
what is the gravitational potential energy of a 55 kg box that is 8 m above the ground? | 4300 J |
what is an example of mechanical energy? | potential energy |
the efficiency of a ramp is 75%. If the amount of work input is 240 J, what is the amount of useful work output? | 180 J |
the brakes on a car exert a frictional force of 6000N in getting the car to stop. if the work done by the brakes is 120,000 J in comming to a stop, how many meters did the car travel after the driver applies the brakes? | 20m |
an object weighing 75N is dropped from the top of a building and falls a distance of 28 m to the ground. how much work does gravity do on the object from the time it is dropped to the time it hits the ground? | 2100J |
the law of conservation of energy states that | energy can neither be created nor destroyed |
temperature is: | associated with the sensation of hot and cold. Proportional to the average kinetic energy of molecules Measured with thermometers. |
as the kinetic energy of the molecules in a substance increases, the: | temperature of the substance increases. |
the transfer of energy caused by the collision of molecules is called | conduction |
the transfer of energy by the movement of fluids or gases with different temperatures is caleld | convection |
Energy from the sun reaches Earth by | radiation only |
convection currents rise in air because | cool air descends and hot air rises |
suppose a fixed number of joules of energy is added as heat to 1 kg of the following substances; liquid ethanol, iron, water, carbon. For which substance will the rise in temperature be the least? | water |
according to the first law of thermodynamics | the total energy used in any process is conserved |
the Fahrenheit temperature scale is defined by which of the following temperatures? | liquid water turns to a gas at 100 degrees and to a solid at 0 degrees |
a cold-blooded reptile basks on a warm rock in the sun. its body is warmed by: | convection and conduction |
a combustion engine uses what kind of energy to do work | heat |
there is a repulsive force between two charged objects when | their charges are of like sign |
when there is an equal amount of positive and negative charges on an object, the object is | neutral |
every charged particle produces | an electric field |
electric field lines | point toward a negative charge, point away from a positive charge, never cross one another |
potential difference is measured in | volts |
batteries typically have | one positive and one negative terminal |
an electric current is produced when charges are accelerated by an electric field to move to a position of potential energy that is | lower |
the SI uit of resistance is the | ohm |
whether or not charges will move in a material depends partly on how tightly _____ are held in the atoms of the material | electrons |
a flashlight bulb with a potential difference of 4.5 V across its filament has a power output of 8 W. How much current is in the bulb filament | 1.8 Amps |
a set of electrical trains are powered by a 9V battery. what is the resistance of the traints if they draw 3 A of current | 3 ohms |
the resistance of an insulator is | high |
appliances connected so that they form a single pathway for charges to flow are connected in a: | series circuit |
a microwave draws 5A when it is connected to a 120 V outlet. If electrical energy cost $0.09/kW/h, what is the cost of running the microwave for exactly 6 hours? | $0.32 |
A device that protects a circuit from current overload is called a(n) | circuit breaker |