Unit 4 Physics
A piece of putty moving with 2 units of momentum strikes and sticks to a heavy bowling ball that is initially at rest. After the putty sticks to the ball, both are set in motion with a combined momentum that is __ _____
2 units
The SI unit of work is ____
J
______ energy is the energy due to the positionof something or the movement of something.
Mechanical
A piece of putty and a rubber ball have the same mass. If you drop them from the same height, which object will produce a greater impulse and why?
Rubber ball, bounces
If the momentum of an object changes and its mass remains constant, it is _____
accelerating
Adding multiple pulleys makes a ____ and ____ system
block, tackle
If your Force is limited, how can you MAXIMIZE the impulse you apply?
by increasing the time of contact
If your change in momentum is constant, how can you MINIMIZE the force applied to you?
by increasing the time of contact
Internal forces come in balanced pairs that _____ within the system
cancel
What are the types of non-mechanical energy?
chemical, nuclear, thermal, electromagnetic
A see-saw at a playground is an example of a ______
class 1 lever
In an isolated system, the total linear momentum is always _____
conserved
In elastic collisions, momentum and energy are ______
conserved
In inelastic collisions, energy is lost to heat or other forms, but momentum is still ______
conserved
When any quantity in physics does not change, we say it is _____
conserved
The total energy in the universe is _____
constant
You an MINIMIZE the force of impact by maximizing the time of ____
contact
Increasing the time of contact will _____ the force of impact
decrease
machines increase output force, and _____ output distance
decrease
A collision is considered elastic if there is no lasting _____
deformation
Wedges and Screws; IMA= ____/_____
depth/ thickness
For an inclined plane a small input force turns into a large output force by spreading it out over a greater _____
distance
A freight train rolls along a track with considerable momentum. If it were to roll at the same speed but had twice as much mass, its momentum would be ____
double
The ratio of useful work output to the total work input is called the ______
efficiency
What is in the middle of a 3rd class lever?
effort
The side of the fulcrum that you push on is called the _____ ______
effort arm
IMA= _____/_____
effort arm/ resistance arm
An _____ collision is when objects collide or rebound without lasting deformation or generation of heat
elastic
Perfectly _____ collisions are not common in the everyday world
elastic
_______ _____ energy is where an object that is stretched will go back to the original shape
elastic potential
Work equals the change in _____
energy
Work involves a transfer of _____ between something and its surroundings
energy
_____ is the ability to do work or cause change
energy
Energy (before) = ______
energy (after)
% _____ _____= (EPE-KE)/EPE x 100
energy lost
The property of an object or system that enables it to do work is ____. Like work, energy is measured in _____
energy, joules
All simple machines ideally work on the principle that work input ____ work output
equals
The momentum of a system cannot change unless it is acted on by _____ forces
external
______ forces are forces that act on a system from outside
external
Inclined planes multiply and redirect ____
force
Machines result in a multiplicationof a _____
force
To increase the momentum of an object, apply the greatest _____ possible for as long as possible
force
When you extend the time, you reduce the ____
force
All levers contain a _____ that they pivot on
fulcrum
What is in the middle of a 1st class lever?
fulcrum
_____ ______ energy is energy that is a result of an objects position or condition
gravitational potential
The impulse required to bring an object to a stop and then to throw it back again is _______ than the impulse required merely to bring the object to a stop
greater
If Newton doubles the length of her wrench, she will need ____ the force to unscrew a struck bolt.
half
A truck at rest has/has no momentum at all.
has no
A force applied over a period of time is called an _____
impulse
No net force means there is no net _____ and thus no change in momentum
impulse
Since ∆p is greater in bouncing situations, the ______ applied will be greater!
impulse
The momentum change of an object is equal to the _____ acting on it
impulse
______ is a change in momentum
impulse
Wedges and screws are a modified ________ _______
inclined plane
In _____ collisions, objects collide and become distorted or generate heat.
inelastic
______ forces are forces that act within a system
internal
If the momentum of an object changes and its mass remains constant, there is/is not a force acting on it
is
If a system is not affected by any net external force, it is said to be _____
isolated
What are the SI units of momentum?
kg·m/s
_____ energy is energy of moving things
kinetic
The two types of mechanical energy are _____ energy and _____ energy
kinetic, potential
If the change in momentum occurs over a short time, the force of impact is _____.
large
a small force applied over a large distance yields a _____ force over a _____ distance
large, small
Inclined plane; IMA= _____/_____
length,height
The work out is always _____ than the work in.
less
A ball is thrown into the air with 100 J of kinetic energy, which is transformed into gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is _____
less than 100 J
SIMPLE MACHINES allow us to do the same job with _____ FORCE, but using ____ ENERGY
less, more
The amount of potential energy possessed by an elevated object is equal to the work done ______ it
lifting
What is in the middle of a 2nd class lever?
load
A cannon recoils from launching a cannonball. The speed of the cannon's recoil is small because the cannon has far more ____ than the cannonball
mass
A moving truck has more momentum than a car moving at the same speed because the truck has more _____
mass
GPE depends on _____ and _____ above the ground
mass, height
KE depends on the ____ and _____ of the object in motion
mass, speed
When energy is lost as heat, it cannot be transformed back to _____ energy
mechanical
A block and tackle system will give an even higher ______ _______
mechanical advantage
What are the two kinds of energy?
mechanical and non-mechanical
If an object has kinetic energy, then it must also have ______
momentum
The ______ of a body is equal to the product of its mass and its velocity
momentum
The concept of inertia in motion is called ______
momentum
When a net force acts upon a body for a period of time, the Impulse applied by the force is equal to the body's change in ______
momentum
A single _____ pulley allows the input force on the right only to support half the weight
movable
The single ____ pulley allows the output force to share the 2 sections of rope pulling upward
movable
When the force applied and the motion are in opposite directions, ______ work is done
negative
Momentum of a system is conserved only when there is no _____ _____ force acting on the system
net external
Work is done when a ___ ___ causes motion
net force
Work is done when a net force acts on an object and the object moves in the direction of the ____ ______
net force
Net momentum (before) = ________
net momentum (after)
What are the SI units of impulse?
n·s
AMA= _______ / ______
output force, input force
Work done on an object divided by the time taken to do the work is called _____
power
Wheel and axle; IMA= _____/_____
radius wheel/ radius axle
Wedges and screws allow for the _____ to be pushed rather than some other object
ramp
The side of the fulcrum that the load is on is called the _____ ______
resistance arm
A karate expert executes a swift blow and splits a cement block with her bare hand. The times of impact on both the block and the expert's hand are the ____
same
A karate expert executes a swift blow and splits a cement block with her bare hand. The forces on both the block and the expert's hand have the _____ ______
same magnitude
A karate expert executes a swift blow and splits a cement block with her bare hand. The impulses on both the block and the expert's hand have the ____ _____
same magnitude
A ____ is an inclined plane Wrapped around a cylinder
screw
A collision is considered elastic if after the collision, the objects have the same ____ as before the collision
shape
What are the two types of pulleys?
single fixed/movable
The spring constant "k" (N/m) is the ____ of the graph Force vs. Stretch
slope
If the change in momentum occurs over a long time, the force of impact is ______
small
A meteor that originally was heading south breaks up into two chunks. One of the chunks moves southwest. The second chunk was not found, but can be guessed that it went _____
southeast
Work is done to change the _____ of an object
speed
Kinetic energy depends on speed ____
squared
A collision is considered elastic if the objects don't _____ _______
stick together
Pulleys; IMA= #_____ supporting the load
strands
A tennis ball launcher is fired. Compared to the impulse on the ball, the impulse one the launcher is ________
the same
Friction Turns Mechanical into _____ Energy
thermal
Suppose a girl is standing on a pond where there is no friction between her feet and the ice. In order to get off the ice, she can ____________
throw something in the direction opposite to the way she wants to go
The reason padded dashboards are used in cars is that they increase the ____ of _____ in a collision
time, impact
In order to catch a ball, a baseball player moves his or her hand backward in the direction of the ball's motion. Doing this reduces the force of impact on the player's hand principally because the ____ of impact is _____
time, increased
When the wheel is turned the axle _____
turns
Momentum is a ____ quantity
vector
If the momentum of an object changes and its mass remains constant, its _____ is changing
velocity
A collision is considered elastic if the objects that collide don't get ______
warmer
What is the SI unit of power?
watts
A _____ is just two inclined planes, back-to-back
wedge
A key is an example of a _______
wheel and axle
Screwdrivers and cranks are common ________ machines
wheel and axle
Energy is the ability to do ____
work
Power is the RATE at which _____ is done
work
_____ is a quantity that measures the effects of a force acting over a distance
work
_____ is the product of the force on an object and the distance through which the object is moved
work
Efficiency= ______/______
work out, work in
