Physics Exam Review- Inertia
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Lizlovesyou4 on September 12, 2011
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81 terms
Terms | Definitions |
|---|---|
 Mass | the quantity of the amount of matter in an object, more specifically mass is a measure of the inertia. "or laziness" of an object that it exhibits in response to any effort made to start it, stop it or, or otherwise change its state of motion. |
| Weight | the force of gravity on an object |
| One Kg weighs | 9.8 newtons |
| The SI unit of force | 1 N |
| The SI Unit of mass | 1 kg |
| Mass is.. | how many atoms are there |
| Newtons first law of motion | "An object at rest will remain at rest, and an object moving at a constant velocity will continue moving at a constant velocit, unless it is acted upon by an unbalanced force." Another name is Law of Inertia |
| weight= mass x acceleration due to gravity | 1 n = (1 kg) x (9.8 m/s^2 ) 1n= 9.8 kh m/s ^2 |
| Formula = | w = m x g |
| Galileo | concluded that if it were not for friction. An object in motion would keep moving forever. |
| Inertia is the | resistance an object has to a change in its state of motion |
| mass is | a measure of inertia |
| mass is not | the same as volume the same as weight |
| The mass of an object depends only on | The number and kind of atoms in it, Mass does not depend on the location of the object. |
| The weight of an object is | The gravitational force acting on it. Weight depends on the location of an object. |
| Net Force | the vector sum of all forces acting on an object- and it affects the objects state of motion. - state of equillibrium net force of 0 |
| When an object is at rest | its weight is balanced by an equal and opposite support force. |
| an object is in equilibrium when it is at rest | WITH ZERO NET FORCE ACTING ON IT |
| equilibrium | A state of balance. - 0 net force |
| force | physical energy or intensity |
| friction | effort expended in rubbing one object against another |
| inertia | the tendency of an object to resist any change in its motion |
| kilogram | one thousand grams SI unit of mass |
| law of inertia | Law stating that objects at rest remain at rest and objects in motion continue in a straight line unless acted upon by a net external force. |
| mass | the amount of matter composing a substance |
| net force | the combination of all forces acting on an object |
| newton | a unit of force equal to the force that imparts an acceleration of 1 m/sec/sec to a mass of 1 kilogram |
| newtons first law | an object at rest will stay at rest, an object that is moving will stay moving unless disturbed by an un balenced force. |
| normal force | the force on an object perpendicular to the surface it rests on. The force doing work. |
| support force | Force that completely balances the weight of an object at rest |
| weight | a unit used to measure weight |
| what distinction did aristotle make between natural motion and violent motion? | natural motion is straight up or down, while violent motion is opposed. |
| why was copernicus reluctant to publish his ideas? | he feared persecution. |
| what is the effect of friction on a moving object? | it slows motion. |
| the speed of a ball increases as it rolls down an incline and decreases as it rolls up an incline. what happens to its speed on a smooth, horizontal surface? | no change (neglecting drag). |
| Galileo found that a ball rolling down one incline will pick up enough speed to roll up another. how high will it roll compared with its initial height? | To the same height if there is no friction. |
| Does the law of inertia pertain to moving objects, objects at rest, or both? | Both |
| the law of inertia states that no force is required to maintain motion. why, then, do you have to keep pedaling your bicycle to maintain motion? | To overcome friction. |
| If you were in a spaceship and launched a cannonball into frictionless space, how much force would have to be exerted on a ball to keep it going? | None |
| Headwind | the two forces are fighting, wind blowing opposite to the path of a ship or aircraft |
| tailwind | wind blowing in the same direction as the path of a ship or aircraft |
| crosswind | wind blowing across the path or a ship or aircraft |
| What heavy object does Dr. Hewitt use to discuss the fact that objects do not move by themselves? | an anvil |
| Who, in fourth century BC, realized that objects move because a force is applied to them? | Aristotle |
| who discovered "the law of Inertia"? | Newton |
| What is the law of inertia? | An object at rest stays at rest, and object in motion stays in motion at a constant velocity, unless the object is acted on by an outside force. - things that rest stay at rest. |
| To say that an object moves in a straight-line path with no change in speed says what about an object's velocity? | klkjl |
| What does Dr. Hewitt suspend over his head connected by a coat hanger to demonstrate inertia? | dfsdf |
| What is inertia, or how much matter an object has, called? | sdsf |
| When Dr. Hewitt pulled the table cloth from under the dishes, they slid forward a little bit but the massive metal cylinder did not move, why? | sdfdsfsd |
| what is the acceleration of a moving object if no net force is applied to it? | sdfsd |
| How heavy something is, the gravitational force on the object, is called the object's? | sdfsd |
| Dr Hewitt had a volunteer hit the anvil with a sledge-hammer rather than directly hitting him. What property did this show? | sdfdssd |
| Objects in equilibrium must have a net force of | 0 |
| Are you shorter or taller in the evening than in the morning? | shorter |
| IF you weigh 150 pounds and distribute your weight equally between two bathroom scales how much will each scale read? | 75 lbs |
| If Harry, a painter, is suspended in a bosun's chair by two ropes, what is the tension of each rope? | half his weight |
| If harry ties one rope to a flagpole so that only the remaining rope supports him, what is the tension in that rope? | all of his weight |
| If harry weighs 200 lbs. but the rope has dry rot that will only support 150 lbs. why wold tying one rope to a flagpole make this harrys last day ont he job? | The rope would break and he would die. |
| Does a 2-kilogram rock have twice the mass of a 1-kilogram rock? Twice the Inertia? Twice the weight (when weighed in the same location) ? | Yes;Yes;Yes |
| Does a liter of molten lead have the same volume as a liter of apple juice? Does it have the same mass? | Yes; No |
| Why do physicists say mass is more fundamental than weight? | Physicists say mass i more fundamental than weight because , Mass is independent of location, while weight depends on the local gravity. |
| An elephant and a mouse would both have zero weight in a gravity-free space. If they were moving toward you with the same speed, would they bump into you with the same effect? | the elephant has more inertia and is harder to stop. |
| What is the weight of 2 kilograms of yogurt? | 19.6 N |
| What is the net force or, equivalently, the resultant force acting on an object in equilibrium? | Zero |
| forces of 10 N and 15 N in the same direction act on an object. what is the net force on the object? | 10N + 15N = 25N |
| If the forces of 10 N and 15 N act in opposite directions of an object, what is the net force? | 15N - 10N = 5N |
| How does the tension in your arms compare when you let yourself dangle motionless by both arms and by one arm? | Double with one arm. |
| A clothesline is under tension when you hang from it. Why is the tension greater when the clothesline is strung horizontally than when it hangs vertically? | The vertical components of the tension vector must add up to the weight, so the vectors along the rope will be very large. |
| If you hold a coin above your head while in a bus that is not moving, the coin will land at your feet when you drop it. when will it land if the bus is moving in a straight line at constant speed? | At your feet because there is no horizontal acceleration. |
| In the cabin of a jetliner that cruises at 600 km/h, a pillow drops from an overhead rack into your lap below. since the jetliner is moving so fast, why doesn't the pillow slam into the rear of the compartment when it drops? what is the horizontal speed of the pillow relative to the ground? relative to you inside the jetliner? | The pillow has the same horizontal speed as the plane; 600 km/h; zero. |
| Calculate in newtons the weight of a 2000-kg elephant. | kjlh |
| Calculate in newtons the weight of a 2.5-kg melon. What is its weight in pounds? | kjlk |
| An apple weighs about 1 N. What is its mass in kilograms? what is its weight in pounds? | jkhjk |
| Susie small finds she weighs 300 N. calculate her mass. | hjjkhk |
| Many automobile passengers suffer neck injuries when struck by cars from behind. How does newtons law of inertia apply here? how do headrests help to guard against this type of injury? | They keep the body and head moving together when the car is suddenly accelerated forward. |
| Suppose you place a ball in the middle of a wagon that is at rest and then abruptly pull the wagon forward. describe the motion of the ball relative to (a) the ground and (b) the wagon. | Except for some change in motion due to friction, there will be no motion of the ball relative to the ground; but relative to the wagon, the ball will move toward the back |
| When a junked car is crushed into a compact cube, does its mass change? its volume? its weight? | No; yes; no; it has the same amount of matter befor and after being crushed. |
| If an elephant were chasing you, its enormous mass would be very threatening. but if you zigzagged, the elephant's mass would be to your advantage. why? | kljkljl |
| When you compress a sponge, which quantity changes: mass, inertia, volume, or weight? | Only Volume; the mass and therefor the inertia are the same because the same amount of matter is present. the weight is the same because there is no difference in gravitational force upon it. |
| is the string tension greater in the upper or lower string? which string is more likely to break? which property, mass or weight, is important here? | kjkljlkjl |
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