Physics Exam
air resistance
a special type of frictional force that acts upon objects as they travel through the air
independent variable
a variable (often denoted by x ) whose variation does not depend on that of another. changes
dependent variable
a variable (often denoted by y ) whose value depends on that of another.
longitudinal wave
a wave in which the particles of the medium vibrate parallel to the direction of wave motion
If all forces are equal, than the net force will equal...
0
how much is required to keep a 3-kg object moving to the right at a constant speed of 6.0 m/s?
0 N
Example for units and conversions: If the radius of the moon is approximately 1730000 m, what will it be in kilometers?
1,730 km
Object A: a 2 kg object moving at 2 m/s object b: a 4 kg object moving at 4 m/s Object A has _____ momentum compared to object b
1/4 as much
an object is accelerating at a rate of 4 m/s squared when it suddenly has its mass increased by the factor 2. The new acceleration will be...
2 m/s squared
The force of gravity of objects on the moon is approximately one sixth of their value on earth. Joe weighs 600 N on earth. Joes mass on the moon will be approximately
60 kg
Alec has a mass of 62 kg. What is Alec's weight on earth?
620 N
transversal wave
A wave that moves up and down
Newton's First Law
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Newton's Third Law
For every action there is an equal and opposite reaction
Newton's Second Law
Force equals mass times acceleration
work
Force exerted on an object that causes it to move
Amplitude
Height of a wave
Crest
Highest point of a wave
frequency units
Hz
In a biology experiment the number of yeast cells in a sample is determined by count after 24 hours of growth at different temperatures- identify the Independent and dependent variables in this experiment
IV: different temp, manipulated or changed by experimenter DV: number of yeast cells, relies on different temps
What property of an object describes its natural tendency to resist acceleration?
Inertia
When a catching a baseball bare-handed, a person will draw their hand backwards in the direction of the ball's motion. The act of drawing the hand backwards is much safer than catching the ball with stiff arms. What affect does this have upon the collision of the ball and the hand?
It causes the time of the collision to be greater and the force to be less
energy units
Joules (J)
work unit
Joules (J)
Units and conversions
King Henry died by drinking Chocolate milk- kilo, hecto, deca, b- (meter, liter, gram), deci, centi, milli
Trough
Lowest point of a wave
Mac and Tosh are arguing in the cafeteria. Mac says that if he flings the Jell-O with a greater speed it will have a greater inertia. Tosh argues that inertia does not depend upon speed, but rather upon mass. Who do you agree with?
Mac
which of the following quantities describes an object's tendency to resist a change in its state of motion?
Mass of an object
What's the difference between mass and weight of an object?
Mass refers to the amount of stuff an object possesses and weight is the force of gravity
Impulse units
N x s
during an egg throwing demonstration, a student threw one egg at a concrete wall, and threw another egg at a hanging bed sheet. The egg that hit the wall exploded on impact, while the egg that hit the sheet landed on the ground, unbroken. Which egg experienced the greater impulse? (hint= impulse=f*t)
Same impulse (both have the same mass, and both came to stop)
Which experiences greater acceleration in a car crash, a butterfly or truck?
The butterfly, it has less mass so it will experience a greater acceleration
net force
The combination of all forces acting on an object
Wavelength
The distance between two corresponding parts of a wave
a large truck traveling at 40 mph down lake avenue collides with a monarch butterfly that is crossing the road. How do forces acting upon these two objects compare to one another?
The experience the same amount of force
Which object has the least inertia?
The one with the least amount of mass
is momentum scalar or vector?
Vector, it has magnitude and direction
power unit
Watts (W)
a rightward object is slowing down. Which of the following statements correctly describes the forces acting upon the object A. the leftward force is stronger than the rightward b. the rightward force is stronger than the leftward c. the rightward force is equal in strength to the leftward
a
which has more inertia: a car or bus?
a bus because it has more mass compared to the car. The car will have a greater acceleration though.
weight
a field force due to gravitational attraction between 2 objects (generally earth and an object)
Applied force
a force that is applied to an object by a person or another object
the following statements were made about a 5-kilogram object. which of the following is true? a. the object weighs 50 N b. the object has a mass of 50 kg c. the force of gravity on the object is 9.8 N
a. the object weighs 50 N
a powerful machine is a machine that...
can do work very quickly
impulse
change in momentum
true or false: faster moving objects have a greater kinetic energy
false, mass is also a factor
Wave speed
frequency x wavelength ( v = f λ ) in m/s
Accuracy
how close a measurement or attempt is to the actual or true value
Precision
how consistent results are regardless of proximity to actual target
How can a student determine if there is a net force or not?
if oppositely-directed forces are unequal, then there must be a net force
Explain the relationship between mass and momentum
increase in mass= increase in momentum INVERSES!!
the reason padded dashboards are used in cars is that they
increase the time of impact in a collision
Which of the following can be explained using Newton's first law of motion?
it explains why a moving object keeps the same velocity
Which of the following can be explained using Newton's second law of motion?
it explains why an object accelerates with a particular acceleration value
what is always true about an object with potential energy?
it's above ground
an object is moving horizontally and slowing down. What is true about it's potential energy?
it's constant
How can a small object have such a large momentum? Like a bullet, for example
its going really fast
an apple falls through the air (just before it hits Newton's head.) Disregard air resistance
just the force of gravity is acting since there is no air resistance.
When all individual forces acting on an object are balanced, it is the natural tendency of an object to _____.
keep its velocity constant (either at a zero or non-zero value)
momentum unit
kg m/s
What is the SI unit for mass?
kilogram
unit for acceleration
m/s^2
what factors does kinetic energy depend on?
mass and speed
the momentum of an object depends upon...
mass and velocity
fg=
mass x gravity (10)
amplitude units
meters
wavelength unit
meters
an object with kinetic energy is an object that's...
moving
in order to have momentum, an object must be...
moving!
a leftward force acts on an object moving to the left. is the force doing positive or negative work?
positive
period units
seconds
Energy
the ability to do work
the mass of an object is decreased. What affect does this have on the acceleration of an object?
the acceleration is increased
the net force of an object is increased. What affect does this have on the acceleration of an object?
the acceleration is increased
Normal Force
the contact force exerted by a surface on an object
friction
the contact force that acts to oppose sliding motion between surfaces
Momentum
the force or speed with which something moves
Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving at 30 miles per hour?
the large track
SI system of measurement
the modern form of the metric system, and is the most widely used system of measurement.
which of the following is known for certain to be true of an object that is at rest?
the object is experiencing a balance of forces
the individual forces acting upon an object are balanced. One can one infer about the object's motion?
the object isn't accelerating
A sled slides down the hill and reaches the bottom where it gradually slows to a stop. The fact that the sled ultimately stops is best explained by
the presence of an unbalanced force
tension
the pull exerted by a string, rope, or cable when attached to a body and pulled taut
Power
the rate at which work is done
in order to catch a ball, a baseball player moves his or her hand backwards in the direction of the balls motion. During this reduces the force if impact on the player's hand principally because
the time of impact is increased
which egg experienced greater force of impact?
the wall- time to stop decreases, so force increases
why did the egg that hit the sheet not break?
time to stop increased, so force decreased
True or false, an object would have a different weight on Earth than it would have on the moon
true
slope formula
y2-y1/x2-x1
