NLN PAX Science: Physics(Answered)
Complete Solution
aim of physics
to understand the physical laws and principles that influence every aspect of daily life
displacement of an object
the distance that an object is from some starting point, and is measured in units of
length
How does displacement change when an object is in motion?
it is constantly changing
How is motion described?
by displacement, velocity (speed) and acceleration
speed
distance traveled by an object per unit of time
speed = (distance traveled/time)
velocity
speed in a given direction
What two things does velocity tell us about a moving object?
its speed and direction
acceleration
the rate of change in velocity; can be any change in velocity, either positive or negative.
deceleration
negative acceleration or a decrease in velocity and can change in direction
How is acceleration calculated?
(final velocity-original velocity)/time
Why can velocity and acceleration be described using vectors?
because they have both magnitude and direction
What quality do all moving objects have?
momentum; an object traveling at a specific velocity has momentum
calculate momentum
Momentum = mass x velocity
conservation of momentum
the total movement of an isolated system is always constant, ie during a collision, the
momentum of each body changes but the total momentum is conserved. One object
may lose momentum, but this momentum is gained by other object
How is momentum conserved when a moving object hits a stable object, such as
a bullet hitting a wall?
the moving object, like the bullet, delivers an impulse to the wall, and this impulse is
said to be the change in the objects momentum
Newton's first law
objects in motion tend to stay in motion and objects at rest tend to stay at rest
inertia
the property of matter that resists any change in motion
Newton's second law
, describes the relationship between force, mass and acceleration; the force of an object
equals the mass of the object times its acceleration
f = ma
newton
the unit that represents a force that accelerates a mass of 1 kg 1 meter per second
friction
force that is exerted on an object along a surface or whenever an object has a velocity
along a surface and the two surfaces touch
gravity
the force of attraction between all objects in the universe
what determines the weight of an object?
the pull of gravity on an object
Why is the Earth's gravitational force great?
because the Earth has a large mass
Is the force due to gravity and the acceleration of an object towards earth the
same?
the force due to gravity is not the same on every object and depends upon the object's
mass, and the acceleration toward earth is the same for all objects, independent of their
mass
How does a change in the force of gravity change an objects weight and mass?
it changes the object's weight but not its mass
density
d=m/v
What is torque and what does it measure?
the perpendicular force times the lever arm; the ability of a force that is applied
perpendicularly to rotate an object around an axis, ie using a wrench to turn a bolt
What is centripetal force?
continual force on an object pulling it towards the center of the circle
What does Newton's third law state?
that for every action there is an equal and opposite reaction
What is energy?
the ability to do work?
What are the two types of energy?
1. Kinetic energy
2. Potential energy
Describe kinetic energy?
energy associated with motion, any moving body has this energy because it is able to
do work by moving other bodies; tells us how much work body can do by moving other
bodies until it is brought to rest
How do you calculate kinetic energy?
kinetic energy = 0.5( mass x velocity)^2
What is potential energy?
the energy stored in a body because of its position, has more potential energy at the top
of a hill than at the bottom
What is work?
Complete Solution
aim of physics
to understand the physical laws and principles that influence every aspect of daily life
displacement of an object
the distance that an object is from some starting point, and is measured in units of
length
How does displacement change when an object is in motion?
it is constantly changing
How is motion described?
by displacement, velocity (speed) and acceleration
speed
distance traveled by an object per unit of time
speed = (distance traveled/time)
velocity
speed in a given direction
What two things does velocity tell us about a moving object?
its speed and direction
acceleration
the rate of change in velocity; can be any change in velocity, either positive or negative.
deceleration
negative acceleration or a decrease in velocity and can change in direction
How is acceleration calculated?
(final velocity-original velocity)/time
Why can velocity and acceleration be described using vectors?
because they have both magnitude and direction
What quality do all moving objects have?
momentum; an object traveling at a specific velocity has momentum
calculate momentum
Momentum = mass x velocity
conservation of momentum
the total movement of an isolated system is always constant, ie during a collision, the
momentum of each body changes but the total momentum is conserved. One object
may lose momentum, but this momentum is gained by other object
How is momentum conserved when a moving object hits a stable object, such as
a bullet hitting a wall?
the moving object, like the bullet, delivers an impulse to the wall, and this impulse is
said to be the change in the objects momentum
Newton's first law
objects in motion tend to stay in motion and objects at rest tend to stay at rest
inertia
the property of matter that resists any change in motion
Newton's second law
, describes the relationship between force, mass and acceleration; the force of an object
equals the mass of the object times its acceleration
f = ma
newton
the unit that represents a force that accelerates a mass of 1 kg 1 meter per second
friction
force that is exerted on an object along a surface or whenever an object has a velocity
along a surface and the two surfaces touch
gravity
the force of attraction between all objects in the universe
what determines the weight of an object?
the pull of gravity on an object
Why is the Earth's gravitational force great?
because the Earth has a large mass
Is the force due to gravity and the acceleration of an object towards earth the
same?
the force due to gravity is not the same on every object and depends upon the object's
mass, and the acceleration toward earth is the same for all objects, independent of their
mass
How does a change in the force of gravity change an objects weight and mass?
it changes the object's weight but not its mass
density
d=m/v
What is torque and what does it measure?
the perpendicular force times the lever arm; the ability of a force that is applied
perpendicularly to rotate an object around an axis, ie using a wrench to turn a bolt
What is centripetal force?
continual force on an object pulling it towards the center of the circle
What does Newton's third law state?
that for every action there is an equal and opposite reaction
What is energy?
the ability to do work?
What are the two types of energy?
1. Kinetic energy
2. Potential energy
Describe kinetic energy?
energy associated with motion, any moving body has this energy because it is able to
do work by moving other bodies; tells us how much work body can do by moving other
bodies until it is brought to rest
How do you calculate kinetic energy?
kinetic energy = 0.5( mass x velocity)^2
What is potential energy?
the energy stored in a body because of its position, has more potential energy at the top
of a hill than at the bottom
What is work?
