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
