Physics 3
A ball is thrown upward and caught when it comes back down. In the presence of air resistance, the speed with which it is caught is
less than the speed it had when thrown upward
Most Natural phenomena we wonder about
involve several scientific disciplines
A force is a vector quantity because it has been
magnitude and direction
Density is the ratio of
mass to volume
In Science, Facts
may change
A baseball player bats a ball with a force of 1000N. The ball exerts is a reaction force against the bat of
1000N
What is the net force on a box that is being pushed to the left with a force of 40N while its also being pushed to the right with a force of 50N
10N to the right
Wind is blowing at 15m/h into rows of wind-powered generators(windmills). What might the wind speed be after it goes through the wind powered generator.
10m/h
A 4Kg ball has a momentum of 12Kg*m/s what is the ball's speed
12/4= v=3 M=V/M= 12/M
A karate chop delivers a force of 3000N to a board that breaks. The force that the board exerts on the hand is
3000N
A girl pulls on a 10Kg wagon with a constant force of 30N. Neglecting friction, what is the wagon's acceleration in m/s2
30n/ 10kg 3m/s2
Which requires more work: Lifting a 50Kg sack vertically 2m or Lifting a 25Kg sack vertically 4m
50*10=f m=25*10=f d=2 d=4 500*2 250*4 1000 1000 Both require the same amount of work
What is the force of gravity on a 500N women standing on Earth's surface
500N
A projectile is launched vertically at 50m/s. If air resistance is negligible, its speed upon returning to its starting point is
50m/s
an object is pulled northward with a force of 10N and Southward with a force of 15N. the magnitude of the net force of the object is
5N
Whereas Aristotle relied on logic in explaining nature. Galileo relied on
experiment
Weight is
the gravitational attraction between you and the earth
If the sun were twice as massive
the pull on the Earth on the sun would double and the pull on the earth would double
In order to catch, a ball a baseball player extends the hand forward before impact with the ball and lets it ride backward in the direction of the balls motion upon impact. doing this reduces the force of impact on the player's hand by
the time of impact is increased
As an object freely falls its
velocity increases
A man weighing 800N stands at a rest on two bathroom scales so that his weight is distributed evenly on both scales, resting on each scales is
400N
What is the force of gravity on a 600N man standing on Earth's Surface
600N
A car accelerates from rest at 2m/s2. What is its speed 3s after the car starts moving?
6m/s
How much force, or thrust must a 20,000kg jet plane develop to achieve an acceleration of 2m/s2
F=MA =20,000kg(2) F= 40,000N
A car has a mass of 1000kg and accelerates at 2m/s2. what is the magnitude of the force exerted on the car
F=MA F=1000kg*2m/s2 F=2000N
The scientist to first introduce the concept of inertia was
Galileo
A kilogram is a measure of an objects?
Mass
Two objects, A and B have the same size and shape, but A is twice as heavy as B, when they are dropped simultaneously from a tower, they reach the ground at the same time, but A has greater
Momentum
Compared with a 1.0kg block of solid iron, a 2.0kg block of solid iron has the same
it doesnt have the same anything, volume, weight and mass.
An object that has kinetic energy must be
moving
The force of gravity acts on all apples on an apple tree. Some apples are twice as far as the other. These twice as far as high apples, for the same mass have
practically the same weight
Science and Technology are
related to one another but not the same thing
A truly educated person is knowledgable about
science, religion, and the arts
It is correct to say that impulses is equal to
the change in momentum
The force that allow you to walk is
the friction of the floor on your foot and the reaction force of your foot against the floor
According to Newton, the greater the masses of interacting object is
the greater the gravitational force between them
Technology
the means of solving a problem by applying the findings of science
The reason that the mood does not crash into the Earth is that
the moon has a sufficient tangential speed.
An example of scientific hypothesis
the moon is made of green cheese
An object is raised above the ground gaining a certain amount of potential energy, if the same object is raised twice as high it gains
twice as much potential energy
An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high it gains
twice as much potential energy
A 1000kg car and a 2000kg car are hoisted the same distance in a gas station. Raising the more massive car requires
twice as much work
A scientific hypothesis may turn out to be right or it may turn out to be wrong, If its a valid hypothesis there must be a test for proving it
wrong
An educated guess is a
Hypothesis
If an object falls with constant acceleration, the velocity of the object must
be constant also
An airplanes flies at 40m/s at an altitude of 50m. The pilot drops a heavy package, which falls and strikes the ground. Where approx does the package land
beneath the plane
Your driving down the highway and a bug splatters on your windshield, which undergoes the greater change in momentum?
both have the same momentum
When a rifle is fired, it recoils so both the bullet and rifle are set in motion, the rifle and bullet ideally acquire equal
but opposite amounts of momentum
In 2.0 seconds, a car increases its speed from 30 Km/h to 35km/h while a bicycle goes from rest to 4 Kim/h. Which has the greatest acceleration?
car v1=30 vf=35 5, 5/2=2.5 bike Vi=0 Vf=4 change 4 4/2=2 the car
A rock is thrown upward at 50 degree with respect to the horizontal. As it rises, its vertical components of velocity
decreases
when a loaf of bed rises, its density
decreases
Mass(quantity of matter) and Weight (force due to gravity) are
directly related to each other
If experimental findings are not reproducible
the results are not considered valid
A ball is thrown upward and caught when it comes back down. Neglecting air resistance, how does the speed, just before it is caught compares to the original speed?
the same as
Railroad Car A rolls at a certain speed and collides elastically with railroad car B of the same mass. After the collision, Car A is at rest. How does the speed of Car B after the collision compare with the initial speed of Car A
the same speed
In Science, A theory is
a synthesis of a large body of well-tested knowledge
The property of a system that enables it to do work
Energy
A moving object has
Energy, speed, momentum and Velocity
When you whirl an object at the end of a string in a circular path what is the direction of centripetal force that acts on the object?
Toward the center
A person weighs 150lbs, the Earth is pulling down on that person with a force of 150 pounds. The person is pulling up on the Earth with a force of 150 pound. True or False
True
In the absence of external work input or output, the energy of a system remains unchanged. Normally energy cannot be created nor destroyed
True
A TV set is pushed a distance of 2m with a force of 20N that is in the same direction as the set moves. How much work is done on the set.
20N*2M=40NM
Which has a greater mass? An automobile battery or a king-sized pillow
an automobile battery
Thinking of the inverse-square relationship, how does the thickness of paint sprayed on a surface change when the sprayer is held twice as far away and the sprayed for the same length of time
1/4 as thick
A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is
0.0N
An apple weights 1.0N when held at rest above your head, the net force on the apple is
0.0N
the force of friction on a sliding object is 10N. The applied force needed to maintain a common velocity is
10 N
Earth's Satellites are typically more than 100km high so as above Earths..... Man made satellites such as the space shuttle orbit at altitudes that are above Earth's
Atmosphere
of the sciences known as physics, chemistry and biology, the most basic is
Physics
The statement "There are regions beneath Earth's Crust that will always beyond reach of scientific investigation is an example of
Speculation
Science
The collective findings of humans, about nature, and a process of gathering and organizing knowledge about nature
When you jump from an elevated position, you usually bend your knees upon reaching the ground. By doing this, the time of impact is about 10 times more for a stiff-legged landing. In this way the average force your body is experiences is reduced by
about 10 times
Hang from a pair of gym rings and the upward support forces of the rings will always
add up equal to your weight
Science, Art and religion do not contradict one another because
all three have different domains
The graph at the right is a graph of \
an indirect proportion
Inside a freely falling runaway elevator, your
apparent weight is zero
What involves passion, talent and intelligence
art, music, science, and literature
A heavy object and a light object are dropped at the same time from rest in a vacuum. The heavier object reaches the ground
at the same time as the lighter object
The two measurements necessary for calculating average speed are
distance and time
Whereas impulse involves the time that a force acts, work involves the
distance that a force acts
According to Newton's law of inertia, the result of walking around much of the day is similar to tightening the head of the hammer when its handle hits a solid surface so that we are actually a little bit but shorter in the
evening
Whirl a rock at the end of a string and it follows a circular path. If the String breaks, the tendency of the rock is to
follow a straight line path
An object is propelled along a straight-line path in space by a force. If the mass of the object somehow becomes twice as much its acceleration
halves
