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the symbol mm represents

millimeter

the SI base unit to measure mass is the

kilogram

if some measurements agree closely to with each other but differ widely from the actual value, these measurements are

precise

five darts strike near the center target. the dart thrower is

accurate

the greek letter delta ▲ indicates a ____
the greek letter sigma Σ indicates _____

difference; change

what are the basic SI units

m kg s

what is the speed of an object at rest

0

a vector makes an angle with the horizontal. the vertical and horizontal components will be the same if the angle is

45°

a golf ball is hit at an angle above the horizontal. what is the acceleration of the golf ball at the highest point in its trajectory? [neglect friction]

less than or equal to 9.8 m/s^2

a ball is thrown from a high window. how far would you describe the acceleration of the ball during its fall?

falls slowly then gradually speeds up

a ball is thrown horizontally from the top of a building with an initial velocity of 15m/p/s at the same instant, a second ball is dropped from the top of the building. the two balls have the same

acceleration and initial vertical velocity

a projectile is launched horizontally from a cliff and eventually hits the ground below. assume the air resistance is negligible. how do the downward and horizontal components of the projectile's velocity behave during the motion

downward- increases horizontal- same

the SI unit for time is a

second

acceleration due to gravity is also called

free fall acceleration

the baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. at what point in the balls path does it experience zero velocity and nonzero acceleration at the same time

at the top of its trajectory

what can be said about the displacement of objects of different masses falling with no air resistance

similar displacements and equal acceleration

how does the velocity of objects that are falling toward earth change as they fall

it becomes greater

which would hit the ground first if dropped from the same height in a vacuum a feather or a metal bolt in the absence of air resistance

neither

which would fall with greater acceleration in a vacuum, a leaf or a stone

neither same acceleration

what is a physical quantity that has a magnitude but no direction

scalar

what is a physical quantity that has both magnitude and direction

vector

what is an example of a vector quantity? what is an example of a scalar quantity?

velocity; temp vol mass

a lightning bug flies at a velocity of 0.25m.s due east toward another lightning bug seen off in the distance. a light easterly breeze blows on the bug at a velocity of 0.25m/s. what is the resultant velocity of the lightning bug

0m/s

what is the motion of objects in two dimensions under the influence of gravity

projectile motion

what is an example of projectile motion? what is not?

a baseball being hit; a jet lifting off a runway

what increases and what stays the same as an object falls freely in a vacuum

velocity increases acceleration stays the same

what is the path of a projectile

a parabola

a basketball player jumps to make a shot. once her feet are off the floor the jumpers acceleration is

-9.8m/s^2

the horizontal component of a projectiles velocity is independent of

the vertical component

a ball thrown through the air will never go as far as physics ideally would predict because of

air friction

suppose you throw a ball straight upward. ignore air resistance. how would you describe the ball acceleration and velocity from the instant the ball leaves your hand until it reaches its highest peak

acceleration is constant velocity decreases

th velocity of an object in free fall on the moon depends on

acceleration of gravity only

what does a force do

starts stops or changes the state of a moving object

what type of forces arise from direct physical contact between two objects

contact force

what type of force exist between objects even in the absence of direct physical contact

field force

what is the tendency of an object to maintain its state of motion

inertia

what is an example of a contact force? what is an example of a field force?

cf- friction normal tension ff- magnetic gravitational electrical

a hammer drives a nail into a piece of wood. identify an action-reaction pair

hammer hits nail nail hits hammer

a free-body diagram of a ball in free fall in the presence of air resistance would show

up Fair down Fn

a car goes forward along a level road at constant velocity. the additional force needed to bring the car into equilibrium is

0

a leaf falls from a tree and lands on a sidewalk. identify an action-reaction pair

leaf pushes on sidewalk sidewalk pushes on leaf

the statement by newton that for every action there is an equal but opposite reaction is which of his laws of motion

third

what are simultaneous equal but opposite forces resulting from the interaction of two objects

action-reaction pairs

the magnitude of the force of gravity acting on an object is called

weight

a box is pushing toward the right across a classroom floor. the force of friction on the box is directed toward the

left

a man is pushing a baby stroller. compared to the magnitude of the force exerted on the stroller by the man, the magnitude of the force exerted on the man by the stroller is

the same

compared to the force needed to start sliding a crate across a rough level floor the force needed to keep it sliding once it is moving is

less

a change in the force of gravity acting on an object will affect the objects

weight

what measures the ability of a force to rotate or accelerate an object around an axis

torque

concerning the amount of torque produced what is true about the position of the force in relation to the axis of rotation

the closer to the axis the more force exerted

the centripetal force is always directed ___________ in circular motion

towards the center

where should a force be applied on a lever arm to produce the most torque

farthest from the axis of rotation

if you want to open a swinging door with the least amount of force where should you push on the door

farthest away from the hinges

if you cannot exert enough force to loosen a bolt with a wrench what should you do

use a longer wrench

the force that seems to cause a rotating object to move away from the center of rotation is a result of the

inertia of object

if the distance between earth and the moon were to increase to twice the present distance the gravitational force between the objects would be _____ the force at the present distance

1/4

which has a greater linear speed: a horse near the outside of the rail of a merry-go-round or a horse near the inside rail? which has a greater angular speed?

outside; neither- same speed

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