| A | B |
|---|
| would a passenger in a moving vehicle be at rest or in motion relative to the driver? | a passenger in a moving vehicle would be at rest because only the car is moving not the passenger |
| distance is | the length of the path between two points |
| displacement | is the direction from the starting point and the length of a straight line from the starting point to the end point |
| displacement vectors of 2 km south, 4 km north, 6 km south and 2 km north combine a total displacement of | 14 km |
| a car traveled 80 km in 1 hour, 100 km in the next two hours, and 75 km in 1 hour before reaching its destination. What was the average speed? | (80+100+100+75)/4 = 63.75 |
| a horizontal line on a distant-time graph indicated that the object is | no moving, there is no acceleration |
| what does the slope of a distance-time graph indicate? | speed |
| what does the slope of a speed time graph indicate | acceleration |
| is it possible for an object to have a constant speed and still be accelerating | yes, it could be changing direction |
| how can vectors be combined | by adding the vectors they would be combined |
| instantaneous speed is the | rate at which an object is moving at a given rate of time |
| average speed is the | total distance traveled divided by the time it takes to travel that distance |
| positive acceleration | is to speed up |
| negative acceleration | is to slow down |
| an example of force | is a man outside in a storm battling the forces of the win |
| the si unit to measure force | is newtons |
| how is the motion of an object affected when balanced and unbalanced forces act on it | it does not change the acceleration |
| what are the four kinds of friction | static, sliding, rolling and fluid |
| static friction is the friction force that acts on objects | that are not moving |
| sliding friction is a force that | opposes the direction of motion of an object as it slides over a surface |
| rolling friction is the | friction that acts on rolling objects |
| fluid friction | opposes the motion of an object through fluid |
| how does earth's gravity and air resistance effect falling objects | gravity causes objects to accelerate downward. Air resistance acts in the direction opposition to the motion and reduces acceleration |
| describe the path of a projectile | a curved path |
| what are the only forces that act on a projectile | air resistance and gravity |
| what is Newton's first law of motion | the state of motion of an object doesn't change as long as the net force acting on an object is zero |
| explain Newton's third law of motion | whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first object |
| momentum equals | mass x velocity |
| what happens when momentum is conserved during a collision | if no net force acts on a system, then the total momentum of the system does not change |
| describe the universal forces acting within the nucleus | two forces, the strong nuclear force and the weak nuclear force, act within the nucleus to hold it together |
| what factors affect the gravitational force between two objects | it always falls out at the same exact time if dropped together |
| in what direction does centripetal force act on an orbiting satellite | it makes it move in a circle |
| identify the appropriate SI units measuring pressure | watts |
| describe the relationship between water depth and the pressure it exerts | water pressure incrases as depth increases |
| describe how forces from pressure are distributed at a given level in fluid | pressure is exerted equally in all directions |
| how does altitude affect air pressure | as you go higher the air becomes thinner so the air pressure is less |
| describe Pascal's principle | a change in pressure at any point in a fluid is tranmitted equally |
| define Bernoulli's principle | as the speed of fluid increases, pressure within the fluid decreases |
| define Archimedes' principle | bouyont force on an object is equal to weight of fluid displaced by an object |
| describe the relationship among object density, and whether an object will sink or float in a fluid | if an object is less dense than the fluid it is in, it will float. If the object is more dense, then it will sink. |
| what conditions must exist for a force to do work on an object | some of the forces must act in the same direction as the object moves. If there is no movement, no work is done |
| what is the formula for wlrk | work=force x distance |
| if you exert a froce of 10 N to lift a box .8m, how much work do you do | 10 x .8 = 8 |
| power equals | work/time |
| how does a machine make work easier | they change the size of the force needed, the direction of the force, or the distance over which the force acts |
| ama equals | ratio of output force to input force |
| what is the equation for ama | output / input |
| why is the efficiency of a machine always less than 100% | there is always some friction |
| lever | a rigid bar |
| screw | inclined machine wrapped around a cylinder |
| wheels | are two disks and cylinders |
| pully | simple machine of rope |
| inclined plane | slanted |
| compound machine | combo of 2 or more simple machines |
