| A | B |
|---|
| force is | is a push or pull |
| force gives what to an object | force gives energy to an object when it causes to start moving change direction, stop moving or changes the shape of the object. |
| Newton's first law | objects remain in motion |
| Newton's first law | objects remain at rest. |
| first law | an outside force is needed to change motion |
| first law | friction a comman force on earth |
| first law | acceleration occures only if forces are not balanced. |
| newton's second law | acceleration and force can not occure with out force. |
| secound law | the harder i push the faster the object accelerates |
| second law | the greater the force the more the acceleration |
| second law | a greater force is required to accelerate the object with greater ineria. |
| second law | force and acceleration must be |
| The law of inertia applies to | x |
| There is a friction force of 10 Newtons between a box and a table top. In order to move the box at a constant velocity, you would have to supply a force | x |
| If you were an astronaut n space and you threw a wrench, the amount of force needed to keep it going would be | zero |
| The amount of matter in an object is called its weight. | False (it's called its mass) |
| The reason a penny thrown straight up inside a bus will come back to your hand is that you, the bus, the air inside the bus, ad the penny are all moving at the same velocity. | true |
| If a hockey puck slides on a perfectly frictionless surface, it will eventually slow down because of its inertia. | false |
| A sheet of paper can be pulled out from under a book without topping it if the paper is jerked quickly. The reason this can be done is that | the book has inertia |
| An object wants to maintain its state of motion because it has | mass (objects want to maintain their state of motion even when they are weightless) |
| If a book weighing 10 Newtons is lyin motionless on a table, the table must be exerting an upward force on the book of exactly 10 Newtons. | true |
| Inanimate objects (like tables and chairs) cannot exert force. | false |
| Suppose a moneky who weighs 80 Newtons is hanign motionless from a branch. The force that the branch exerts on the monkey is ___ Newtons. | 8 |
| Excluding the force due to air pressure, there is only one force acting on a book lying at rest on a tabletop. | false (If a book is at rest, its acceleration is zero. By Newton's First Law, if the acceleration of the book is zero, the net force on the book must be zero) |
| For an object to be in static equilibrium, the upward forces on the object must exactly balance the downward forces. | true |
| A girl whose weight is 300 Newtons hangs (motionless) from a bar supported by two strnds of rope. Assuming that she exerts an equal force on each rope, what is the tension in each rope? | about 200 Newtons |
| the ame of the force that just balances the weight of a book lying at rest on a tabletop is called a normal force. | true |
| If an object is not accelerating, it is in | equilibrium. |
| Equilibrium is often considered as two separate cases: | Static Equilibrium - An object is at rest and not accelerating;Dynamic Equilibrium - An object is moving (relative to us) and not accelerating. |
| Suppose that Abe and Betty are riding in a car on a long straight road - Abe is in the back seat, and Betty is in the front seat. Charlie is standing beside the road.Suppose that Charlie notices that the car takes 5.0 seconds to move between 2 marks on the road that Charlie has previously measured to be 40 meters apart. Charlie calculates Betty's speed (Betty is in the car, remember) as 40 m/5.0 s = 8.0 m/s relative to Charlie (or relative to the Earth).During this same 5.0 seconds, Abe observes (Abe is also in the car) that Betty has remained motionless - he calculates Betty's speed as 0.0 m/5.0 s = 0.0 m/s relative to Abe (or relative to the car).What is Betty's correct speed? 8.0 m/s or 0.0 m/s? | both are correct |
| True/False inertia is not a force - | True |
| Inertia is a property of matter, | True |
| True/False All objects made of matter obey Newton's First Law - regardless of how much inertia they have. | True |
| What is the explanation? Your car is at rest. Suddenly you push down on the "accelerator" and the accelerates forward. You feel that you are pushed back into your seat. | You were at rest, you remain at rest. The car accelerates forward, and you stay where you are. |
| What is the explanation? You are moving at constant velocity (constant speed in a straight line). Suddenly you apply the brakes. You feel "thrown forward" into the dashboard! | You are moving with a constant velocity. You keep that velocity (while the car slows down) until something stops you. |
| What is the explanation?You go around a curve (at constant speed). You feel pulled toward the outside of the curve. | You were moving with a constant velocity (straight line at constant speed). The car turned, and you didn't (since Newton's First Law says your velocity stays the same unless an unbalanced force acts on you. |
| If you push harder, you get more | acceleration, |
| direct proportion or direct variation is | double one thing, the other doubles |
| True/False | The acceleration is directly proportional to the net force applied. |
| True/False The net force also determines the direction of the acceleration - | true |
| If the net force on an object is zero, its acceleration will be | zero |
| If no forces act on an object, the net force on the object is . | zero |
| If there is just one force on an object, then that force is the | net force. |
| If 2 forces push or pull on an object in opposite directions, and the two forces cancel each other exactly, the net force is | zero |
| If two forces act on an object in opposite directions and they don't exactly cancel, what is left over is the | the net force |
| If two(or more) forces act on an object in the same direction, the net force is | the sum of the forces. |
| The force that is "left over" after all of the forces acting on an object are cancelled and/or combined is called the net force. | true |
| A 3 Newton force ad a 7 Newton force act in the same direction on a moose. What is the magnitutde of the net force on the moose? | 10 Newtons |
| A 3 Newton force and a 7 Newton force act in opposite directions on a moose. Th magnitude of the net force on the moose is | 4 Newtons |
| Friction refers to the force between two surfaces that are sliding past one another. | true |
| A force can be defined as a push or pull exerted by one material object on another. | true |
| The Sl (metric) unit of force is called the kilogram. | false |
| Newton's Second Law says | that the acceleration of an object equals the net force on it divided by its mass: |
| How much horizontal net force is required to accelerate a 1000 kg car at 2 m/s2? | 2000 Newtons; Newton's 2nd Law relates an object's mass, the net force on it, and its acceleration |
| What acceleration will result when a 12-N net force applied to a 3-kg object? A 6-kg object? | x |
| A net force of 16 N causes a mass to accelerate at a rate of 5 m/s2. Determine the mass. | x |
| If a hockey puck slides on a perfectly frictionless surface, it will eventually slow down because of its inerria. | false (Newton's first law says that if no force acts on an object, it will never slow down.) |
| If you slide a hockey puck across a frictionless path, there must e a horizontal force on it to keep it in motion. | false (Newton's first law says that if the net force on an object is zero, the object will not accelerate.) |
| Inertia is the property that every material object has that causes the object to resist changes in its state of motion. | true |
| The amount of matter in an object is called its weight. | false (the amount of matter in an object is called its mass.) |
| The reason a penny thrown straight up inside a bus will come back to your hand is that you, the bus, the air inside the bus, and the penny are all moving at the same velocity. | true |
| There is a friction force of 10 Newtons between a box and a table top. In orde to move the box at constant velocity, you would have to have to supply a force | of 10 Newtons |
| The law of inertia applis to | moving and nonmoving objects |
| The law of inertia states that an object | will continue to moving at the same velocity unless an outside force acts on it; will continue moving ina straight line unless an outside force acts on it; at rest will remain at rest unless acted on by an outside force; that is not moving will never move unless a force acts on it |
| a sheet of paper can be pulled out from under a book without topping it if the paper is jerked quickly. The reason this can be done is that | the book has inertia |
| If you were an astronaut in space and you threw a wrench, the amount of force needed to keep it going would be | zero |
| If the force of gravity suddenly stopped acting on the planets, they would | move in a straight tanget to their orbit |
| When a football is kicked, the action and reaction forces do not cancel each other because | they act on different objects (the kicker's foot and the ball) |
| If a horse pulls a wagon that is at rest, the wagon pulls back equally as uch on the horse. Assuming that there is negligible friction acting on the wagon, will the wagonbe set in motion? | Yes, because there is a net force acting on the wagon. |
| "Whenever an object exerts a froce on another object, the second object exerts a force of the same magnitude, but inthe opposite direction to that of the first object. This statement is | always true |
| A bicycle and a parked car have a head-on collision. The force of impact is greater on the bicycle. | false |
| In order to make a wagon move forward, a horse must pull harder on the wagon than the wagon pulls on the horse. | false |
| A rocket is pushed forward by the exhaust gasses that are forced out of the back of the rocket by its engine. | true |
| a carpenter hits a nail with a hammer. During the collision, there is a force | on the nail and on the hammer |
| Two people pull on a rope in a tug-of-war. Each pulls with 100 Newtons of force. The tension in the rope is | 100 Newtons |
| a car accelerates along a road. Viewed from outside the car, what is the force that accelerates it? | The road is pushing the car forward. |
| An unfortunate bug splatters agaist the windshield of a moving car. Compared to the force the care exerts on the bug, the force the bug exerts on the car is | the same |
| An unfortunate bug splatters against the windshield of a moving car. Compared to the deceleration of the car, the deceleration of the bug is | larger |
| Forces always occur | in pairs |
| A large Mack truck ad a small Volkswagen traveling at the same speed have a head-on collision. The vehicle to undergo the greater change in elocity will be the | volkswagen |
| a person is attracted toward the center of the Earth by a 500 Newton gravitational force. The force with which the Earth is attracted toward the person is | 500 Newtons |
| Whenever one object exerts a force on another object, the second object always exerts an equal force back on the first object. | true |
| The product of mass and velocity is | momentum. |
| The tendency of an object to resist change in its motion is called | inertia. |
| Any force that causes an object to move in a circle is called a(n) | centrifugal force. |
| As a car stops suddenly your body continues to move forward. This is an example of | Newton's first law. |
| Which of these surfaces has the least amount of friction? | ice |
| According to Newton's second law of motion, if the force acting on an object stays the same but the mass of the object increases, then acceleration will | decrease. |
| The force of gravity acting on an object is known as its | weight. |
| Astronauts were able to leap easily on the moon because | the moon's gravity is weaker than Earth's. |
| A change in the motion of an object is caused by a(n) | unbalanced force. |
| When two objects collide in the absence of friction, | the total momentum stays the same. |
| A Ferris wheel moving at constant speed is accelerating because the | direction is always changing. |
| To calculate acceleration, you need to know the | final velocity, initial velocity, and the total time. |
| To determine the velocity of a moving object, you need to know both its speed and its | direction of motion. |
| The basic SI unit of length is the | meter. |
| Earth's plates move slowly in different directions according to | the theory of plate tectonics. |
| A graph of distance versus time for an accelerating object is a | line curving upward. |
| An object is in motion when it changes position relative to | a reference point. |
| Which of the following is the correct relationship between speed and distance? | Speed = Distance / Time |
| The plates that make up Earth's surface move at speeds of | centimeters per year. |
| To calculate average speed, you need to know | the total distance traveled and the total time. |
| A five kilogram fish swimming at a velocity of 1 m/s swallows an absent minded 1 kg fish at rest. The speed of the larger fish after lunch is: | 5/6 m/s |
| A 1000kg car traveling at 10 m/s brakes to a stop in 5 s. The average braking force is: | 2000N |
| A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun | if the mass of the bullet equals the mass of the gun |
| Two freshmen, Ted and Marcy are dropped from the roof of the school. Ned is twice as heavy as Marcy. Ignoring air friction, the reach the ground at the same time, but Ted has a greater: | momentum |
| Suppose a gun was made of a strong but very light material. Suppose also that the bullet is more massive than the gun itself. For such a weapon: | the target would be safer than the shooter. |
| It is correct to say that impulse is equal to | the change in momentum |
| The difference between impulse and impact force involves: | time the force acts |
| A freight train rolls along a track with considerable momentum. It a second train rolls at the same speed but has twice as much mass, its momentum is: | doubled |
| Which of the following has the largest momentum relative to earth? | A pickup truck speeding along a highway |
| If the net external force acting on a system is zero, then the total momentum of the system is zero. | false (if the net external force (the impulse) acting on a system is zero, then the net change in momentum of the system is zero) Momentum will not change |
| When a bug collides with the windshield of a car, the change in momentum of the bug is | equal to the change of moimentum of the car |
| If the net external force acting on a system is zero, then the total momentum of the system is constant. | true (law of conservation of momentum) |
| When two objects collide and completely bounce apart with no lasting deformation or generation of heat, the collision is said to be elastic. | true (this is the definition of elastic collision) |
| momentum is conserved in elastic collisions. | true (momentum is conserved whenever there is no external forces acting on a system) |
| When a bug collides with a car's windshield, the impulse exerted on the bug by the car is | equal to the impulse exerted by the bug on the car |
| The Law of Conservation of Momentum says that the total momentum of any group of ojjects remains the same if no outside forces act on the objects. | true |
| A moving freight car collides with an identical freight car at rest on the same track and the cars couple together. Compared to the speed of the first car before the collision the speed of the coupled cars after the collision is | half as much |
| A 2 kg chunk of putty moving at 5 m/s collides with and sticks to a 5 kg bowling ball that is initially at rest. The bowling ball with its putty attached will then be set in motion with the momentum of | 10 kg m/s |
| When two objects collide and completely bounce apart with no last deformation or generation of heat, the collision is said to be inelastic. | false (when two objects bounce apart the collision is elastic) |
| Impulses are smaller when bouncing takes place. | false (impulses are larger when bouncing takes place |
| Momentum is conserved in inelastic collisions, but not in elastic collisions. | false (momentum is conserved whenever there is no external forces acting on a system |
| Momentum is conserved in every case in which no net external force acts on a system. | true (this is the conservation of momentum) |
| All movement is compared with a | frame of reference |
| The most commonly used frame of reference is | the earth |
| a change in position relative to a frame of reference is | motion |
| The rate at which an object changes position | SPEED |
| Velocity is speed and | direction |
| If a motorboat travels 25 km/hr down a river that has a velocity of 4 km/hur, what is the boat's actual velocity? | 29 km/hr |
| the rate of change of velocity is called | acceleration |
| A distqance time graph is a straight line for | constant speed |
| An object traveling in a circular motion is constantly changing | direction |
| Momentum is mass times | velocity |
| Force is | a push, a pull, or a the ability to change motion |
| Froces that are opposite and equal are called | balanced forces |
| The force that opposes the motion of an object is called | friction |
| The type of friction that exists for a shark swimming in the ocean is | fluid |
| The property of matter that resists a change in motion is | inertia |
| According to Newton's second law of motion, force equals mass times | acceleration |
| A change in the force of gravity pulling on you will change your | weight |
