Physics: Chapter One and Two

a ball is thrown straight up. at the top of its path its instantaneous speed is

0 m/s

a body at the end of a spring oscillates up and down ten times in five seconds. the period of oscillation is...

0.5 s

what is the displacement of a person who walked 40 m north, 20 m east, and then 40 m south?

20 m east

you whirl a 2 kg body attached to a 1 meter cord around your head in a nearly horizontal circle with a speed of 4m/a. the tension in the cord is

32 N

you push on a block on frictionless ice with a force of 8 N, causing it to accelerate at 2m/s2. the mass of the block is

4kg

suppose a car is moving in a straight line and steadily increases its speed. it moves from 45 km/h to 50 km/h the first second and from 50 km/h to 55 km/h the next second. what is the car's acceleration?

5 km/h*s

a race car driver steps on the gas, changing his speed from 10 m/s to 30 m/s in 4 seconds. the acceleration of the race car is

5 m/s2

a car starts from rest and after 5 seconds it is moving at 30 m/s. what is the car's average acceleration?

6 m/s

if a projectile is fired straight up at a speed of 30 m/s, using g=10m/s2 the total time to return to its starting point is about

6 s

suppose you take a trip that covers 120 km and takes 2 hours to make. your average speed is

60 km/h

a race car goes around a 200m radius curve at a constant speed of 40 m/s. its acceleration is

8 m/s2

when something falls to the ground, it accelerates. this acceleration is called the acceleration due to gravity and is symbolized by the letter g. what is the value of g on earth's surface.

9.8 m/s

a ball is thrown straight up. at the top of its path its acceleration is

9.8 m/s2

if a freely falling object were somehow equipped with a speedometer, its speed would increase each second by..

about 5 m/s

in the absence of air resistance, objects fall at constant

acceleration

the slope of a velocity v. time graph is the

acceleration

as an object falls freely in a vacuum, its...

acceleration increases

the acceleration of a body is...

always in the same direction as the net force of the body

speed is

always measured in terms of a unit of distance divided by a unit of time, the distance covered per unit time, a measure of how fast something is moving.

an object moving in a circle undergoes

centripetal acceleration

the force needed to make an object move in a circle is...

centripetal force

in expressions like v and t, stands for

change in

motion in a circle at constant speed is motion with

constant acceleration

motion in a straight line with increasing speed

constant net force in the same direction as velocity

motion in a straight line with decreasing speed

constant net force opposite to velocity

motion in a circle

constant net force perpendicular to velocity

the vertical speed of a projectile

decreases and sometimes increases

a ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. during this time the acceleration of the ball is always

directed downward

the vertical acceleration of a projectile

equals g pointing downwards

true or false: as a projectile moves its speeds stays constant while its direction changes

false

true or false: at the peak of its motion, the acceleration of a projectile is zero.

false

true or false: when a body moves in a straight line with increasing speed, the net force on it must be increasing.

false

true or false: when a body moves with uniform acceleration, the net force on its zero.

false

if you whirl a tin can on the end of a string and the string suddenly breaks, the can will..

fly off, tangent to its circular path

instantaneous speed and average speed are equal

for motion at constant speed

the number of cycles of a periodic process that occurs per unit time is called

frequency

the pitch of a note when a piano key is struck

hz

units: frequency of a body vibrating at the of a spring

hz

when you look at the speedometer in a moving car, you can see the car's

instantaneous

a car travels in a circle with constant speed. the acceleration on the car...

is directed towards the center of the curve

if the velocity of an object is negative,

it is moving in the direction labeled negative

when a freely object reaches its terminal speed

its acceleration is zero

the metric prefix that means one thousand is

kilo

the mass of a baseball

kilograms

the distance between your school and your home

meters

the speedometer reading your car

meters/seconds

the quantity describing how the speed of your car changes

meters/seconds 2

units: air resistance

meters/seconds 2

units: the quantity that measures the resistance of an object to being accelerated

meters/seconds 2

one possible unit of speed is

miles per hour, kilometers per hour, light years per century

freely falling bodies experience

motion with constant acceleration

the force exerted on a baseball by a baseball bat

newtons

units: static and kinetic friction

newtons

units: the gravitational pull of the earth on the moon

newtons

your weight

newtons

the time for one complete cycle of a periodic to take is called...

period

simple harmonic motion

restoring force proportional to displacement

what is the proper abbreviation for "seconds"?

s

the reading on a watch

seconds

the force that keeps your feet from sliding as you walk is...

static friction

the horizontal speed of a projectile

stays constant

isaac newton's contributions to physics include...

the law of motion, the law of universal gravitation, invention of the calculus, the invention of the reflecting telescope

if the net force on an object is zero,

the object's acceleration must be zero

acceleration is defined as..

the rate at which velocity itself changes

samuel throws a rock downward, and air resistance is negligible. compared to a rock that is dropped, the acceleration of the rock after it is thrown is..

the same

a ball is thrown upward and caught when it come back down. in the absence of air resistance, the speed of the ball when caught would be

the same as the speed it had when thrown upwards

when a body moves in circular motion at constant speed

the velocity and acceleration point in the same direction

as the ball is going upwards

the velocity points upward and the acceleration down

two cars crash head on. at any given during the crash, the magnitude of the collision forces exerted on each car are exerted on each car are exactly equal. this is an example of newton's...

third law

true false: as you go high and higher above the surface of the earth, the mass of a body stays constant.

true

true or false: "net force" means the vector sum of all the individual forces acting on a particular body.

true

true or false: all force have specific directions associated with them

true

true or false: as you go from a point where a gravitational field is strong to a point where the gravitational field gets weaker, the gravitational field lines get farther apart.

true

true or false: the direction of a field line at a point in space shows the direction of the force that would act on a body placed at the point.

true

true or false: the weight of an object equals its mass times the acceleration of gravity.

true

true or false: when an object reaches its terminal speeds, its acceleration is zero

true

true or false: you are presently exerting a gravitational forces acting on a particular body

true

the symbol G is used to represent...

universal gravitational constant

the slope of a distance v. time graph is the

velocity

acceleration is defined as the change in?

velocity divided by the time interval

suppose you are in a car that is going around a curve. the speedometer reads a constant 30 miles per hour. which of the following is NOT true?

your velocity is constant

a body reaching a terminal velocity

zero net force

motion in a straight line at constant speed

zero net force

a child on a swing swings back and forth 25 time in 35 seconds. what is the frequency of the swing?

1.4 hz

what is the period of a signal that has a frequency of 60 hz?

1/60 hz

a station wagon accelerates at 2 m/s2. assuming the station wagon starts from rest, how much time does it need to accelerate to a speed of 20m/s?

10 s

using g=10m/s2, a freely falling object starts from rest. after falling for 10 seconds, it will have speed of about...

100 m/s

if a ball were equipped with a speedometer and allowed to fall freely on a planet where the acceleration due to gravity is 16 m/s2 , the reading on the speedometer would increase each second by...

16 m/s