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| You have 2 photos of a person walking. 1 shows the person at the corner of 3rd and main streets, the other shows the person at the corner of 10th and main streets. there are lampposts at every corner in this town, and the first pic shows it to be 10:32 ex |
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| a tube of air contains a feather and a coin. both objects are dropped at the same time. the soin falls faster than the feather. however, when the air is removed from the tube to create a vacuum, both the feather and the coin reach the bottom at the same t |
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| without the force of gravity, all objects have the same weight, and therefor fall at the same speed |
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| using the terms acceleration, velocity, speed and inertia, explain why wearing a seat belt saves lives. also explain why shoulder belts and lap belts used together are more effective than lap belts alone. |
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| when you accelerate, you're forced backwards, the speed of the car increases, as does your inertia. when you stop, your body wants to go forward, and that is when your seatbelt holds you back from flying out the front windshield. just using a lap belt, your velocity would make the top part of your body fly forward is you abrubtly stopped. |
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| because the speed of an object can change from one instant to the next, dividing the distance covered by the time of travel gives |
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| when an object is seen moving against a statinoary background, what is the stationary background called? |
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| if an object traveling in one direction has a positive velocity, what kind of velocity would the same object traveling in the oppposie direction have? |
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| which has greater momentum, a small pick-up truck traveling 55 mi/hr or a full-sized bus traveling at the same speed? |
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| a large truck loaded with scrap steel weighs 14 tons and is traveliong north on the interstate heading fro Chicago. It has been averaging 48 mi/hr for the journey and has traveled over 1450 miles so far. It has just stopped to refuel. what is its current |
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| If two objects with different masses and traveleing with different velocities collide, what law allows you to predict the motion of the objects after the collision. |
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| A small sports car traveling south collides with a heacy truck traveling north. both vehicles are going at the same speed. which will be moved off course by collision and in which direction? |
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| the small sports car, north |
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| If two vehicles collide, name at least one outside force thay will come into effect immediately after the impact and cause the objects to eventually come to a stop. |
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| change in velocity divided by the time interval in which the change occurred. |
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| in your own words, explain the similarities and differences between velocity and acceleration. |
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| velocity describes speed and direction whereas acceleration describes the change in velocity divided by the time it took for the change to happen. both involve speed and direction |
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| explain why a cyclist accelerates when turning a corner even if her speed doesn't change. |
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| because she is changing her direction, which is a change in velocity, which is acceleration |
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| during a race, a sprinter increases from 5.0 m/s to 7.5 m/s over a period of 1.25 s. what is the sprionter's average acceleration during this period? |
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| two archers shoot identical arrows at a target from exactly opposite directions. use your knowledge of net forces to describe the movement of the target. |
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| the target won't move because the forces cancel each other out. |
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| Distinguish between balanced forces and unbalanced forces. |
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| balanced forces combine to produce a net force equal to zero whereas unbalanced forces combine to produce a net nonzero force |
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| what will the result be if two equal forces act on a single object from different directions that are not exactly opposite? |
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Definition
| it will move in one direction. |
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| why is it easier to push a crate over a smooth concrete sidewalk than over grass? |
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Definition
| because the grass has more friction which takes more force |
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| you are pushing a heavy crate across a cement floor when you hit a section of flooring covered with smooth stell plates. suddenly it is somewhat easier to push the crate. why? |
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| the plates have less friction than the floor |
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| list two situations in which friction is helpful or necessary. |
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1. hitting the brakes of a car
2. a car parked on a hill |
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| state newton's first law. |
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| an object at rest remains at rest and an object in motion maintains its velocity unless it experieces and unbalanced force. |
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| state newton's second law. |
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| the unbalanced force acting on an object equals the object's mass times its acceleration |
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| express the following as an equation: One newton is the force that can give an object with a mass of 1 kg an acceleration of 1 m/s^2. |
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| rearrange the equation for newton's second law of motion to define acceleration in terms of force and mass. |
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| the motion of a body when only the force of gravity is acting on it |
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| where is the free fall acceleratino of an object under earth's gravity directed? |
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Definition
| toward the center of the earth |
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| what is the value for the acceleration of objects in free fall near earth? |
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| in the abscence 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 |
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Definition
| the rock would hit the ground first and then the book |
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| does the direction of an object falling toward differ from the direction of an object falling through water on earth? why or why not? |
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Definition
| no, because they both fall toward the center of the earth |
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| what is the difference between mass and weight? |
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Definition
| mass is a measure of the amount of matter in an oject whereas weight is the gravitational force an objecty experiences due to its mass |
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| how does gravity influence the shapes of living things? |
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Definition
| depending on the location of an animal/object, that animal will either be a vertabrate or an invertabrate and that object's structure will be sturdier/weaker |
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Term
| define terminal velocity. |
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| the maximum velocity reached by a falling object that occurs when the resistance of the medium is equal to the force due to gravity |
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| how would the terminal velocity of an object falling toward earth differ from the terminal velocity of the same object falling through water and why? |
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Definition
| the terminal velocity of an object falling toward earth would be greater than that of the same object falling through water because water has more resistance than air and would slow the object down more |
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| why does it require less fuel to accelerate a rocket in outer space than required in earth's atmosphere? |
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Definition
| because air is more dense on earth |
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| what is the velocity of an object called when gravitational forces and air resistance equalize on an object that is falling toward earth and the object stops accelerating? |
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| when an object covers equal distance in equal amounts of time, it is moving at a(n) ____ speed. |
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| velocity describes both speed and ____ |
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| mass times velocity equals ____ |
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| according to newton's second law of motion, force is the product of ____ and ____ |
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| what is the approximate terminal velocity of a sky diver before the parachute opens? |
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| which of the following does nto indicate velocity? |
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Definition
| d) 28 miles from Los Angeles to Catalina Island |
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| The difference between speed and velocity is that velocity includes |
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Definition
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| which of the following is not a factor in calculating momentum? |
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Definition
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| if you divide momentum by velocity, the result is the value of the object's |
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| whenever an object is standing still, the value(s) that is/are always zero is/are |
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| a 10.0 kg dog chasing a rabbit north at 6.0 m/s has a momentum of |
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| if you are given the mass of an object in punds, the time in seconds, and the distance in feet, what must you do before you can calculate the momentum in SI units? |
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| acceleration is defined as the change in velocity divided by |
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Definition
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| the SI unit for acceleration is |
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Definition
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| on a velocity-time graph, a line with a negative slope indicates that the object is |
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Definition
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| when the velocity of an object changes, it is acted upon by a(n) |
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Definition
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| the combinations of all the forces acting on an object is called the |
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Definition
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| If the net force acting on a stationary object is zero, then the object will |
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Definition
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| If the net force on an object is zero then the object has |
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| a tug-of-war that results in one team pulling the other across the line is an example of |
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Definition
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| which of the following best illustrates balancede forces? |
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Definition
| b) a stretched rubber band being held between two hands |
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Definition
| a) force that opposes motion between two surfaced that are touching |
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| a force is continuously applied to an object, causing it to accelerate. after a period of time, however, the object stops accelerating. what conclusions can be drawn? |
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Definition
| c) the object is experiencing some kind of friction |
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| which of the following situations best demonstrates the effects of friction? |
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| an airplane is flying at 635 miloes per hour at an altitude of 35 000 feet. it is currently over Kansas and is approximately 16 minutes ahead of its scheduled arrival time. what is its velocity? |
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Definition
| d) this cannot be determined without further information about its direction. |
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| which of the following statements is true? |
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Definition
| a) frictional forces are greatest when both surfaces are rough. |
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| weight is best described as |
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| c) the downward force exerted on objects due to gravity |
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| when objects are moved further apart from each other, the force of gravity |
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Definition
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| of the following, the greatest gravitational force would occur between |
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Definition
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| the law that states that every object maintains constant velocity unless acted on by an unbalanced force |
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Definition
| a) newton's first law of motion |
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| the law that states that for every action force there is an equal and opposite reaction force is |
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Definition
| c) newton's third law of motion |
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| the law that states that the unbalanced force acting on an object equals the object's mass times its acceleration is |
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Definition
| b) newton's second law of motion |
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Term
| the SI unit of force, named for the scientist who described the relationship between motion and force, is called the |
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Definition
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| one pound is equal to how many newtons? |
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Definition
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| which of the following units is used to measure acceleration in free fall? |
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Definition
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| which of the following equations is correct? |
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Definition
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| which of the following is true? |
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Definition
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| when air resistance balances the weight of an object that is following, the velocity |
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| the distance traveled by an object divided by the time it takes to travel that distance is called |
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Definition
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| in order to determine speed, you must know |
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| what is the speed of an object at rest? |
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