Work and Energy
Watt
1 j/sec = 1 _______ (what unit)?
1
550 ft-lb/sec = ____ H.P.
6,000, 6,000, 6,000
A 500 lb pile driver is raised to a height of 12 feet, then dropped _______ ft-lbs of work is done The increase in the pile driver's potential energy is _____ ft-lbs What is the maximum kinetic energy the pile driver will have after it is released is _____
5 Joules
A box of groceries requires five newtons of force to lift it one meter to the counter. How many joules of work is done
12, 12
A box weighing 4N is lifted 3 m. The work is done on the box is ____ joules The potential energy the box possesses at the top is ____joules
100 Joules
A man weighing 50 newtons climbs a 2-meter ladder. How many joules of work is done?
car
A motorcycle and a car are driving next to each other on the freeway. The _______ has the greater inetic energy
1,100 ; 2
An elevator weighing 2,200 lbs is raised one story in 20 seconds. If the distance between stories is 10 feet, the power is developed by the elevator motor is ____ ft x lb/s. The power of the motor required for the elevator is _____ H.P.
P.E. converts to K.E.
As an object is in free-fall to the ground___ K.E. = P. E P. E. converts to K.E K.E. converts to P. E. P.E. = zero
Newton meter
Each joule of work is one _________ (units) of energy
work
Energy is often measured by the amount of ______ accomplished
kinetic energy
Energy of motion; the energy available as a result of the motion of a body is called _______
horsepower
English system unit of power, equivalent to 746 watts
weight x height
How is P.E. calculated? mass X velocity mass x distance weight x height mass x height
30 joules
How many joules of work is done when a force of 10 newtons is used to lift a boy 3 meters in the air?
The force must be in the same direction as movement
In the math equation W= F x D, what relationship is required for work to be accomplished? The force must be greater than the distance The force must be equal to the distance the force must be perpendicular to the distance the force must be in the same direction as movement
thermodynamics
James Joule is credited with founding the science of ____________________
mass; speed
Kinetic energy is related to the _______ of an object and its ________
joule
Metric unit of work and energy equalto one newton times one meter
height, ground
Potential energy results from an object's ________above the _______
rate
Power is the _______ of doing work
False
T/F It is not possible for a very small engine (low power output ) to do a great amount of work
False
T/F Potential energy is related to the speed of an object
False
T/F Work against gravity is done if you carry a book across a room
True
T/F Work is done if water falls from the top of a dam
True
T/F Work is done if you lift a brick
True
T/F Work is done if you push a box across a room
True
T/F Work is done if you push a child in a wagon
False
T/F Work is done if you push against a wall
Law of Conservation of Matter and Energy
The First Law of Thermodynamics is generally referred to as____________ First Law of Motion Joule's Law E= IR 2 Law of Conservation of Matter and energy Universal Gravitation
work
The product of force and the distance through which it moves
Power
The rate of doing work __________
Joule
The standard unit of work in the metric system is named after the scientist ________________
force, distance, time
The three factors required to determine power requirements for a task are: Force, mass, distance, gravity, time
potential
The total work required to raise a mass to a position above the earth is equal to the ________ energy it now possesses at that position
One going 60 MPH
Two pick-up trucks (identical in size and mass) are moving down a highway; One truck is going 40MPH ahead of the other going 60 MPH. Which truch has the greater K.E.?
equals weight
When raising an object vertically, the force required: equals mass equals weight is greater than mass is greater than weight
The law is completely consistent with the Bible's account of Creation The Law confirms that matter or energy could not create itself The law shows that the total amount of matter and/or energy in the universe is constant (does not change
Which Statement(s) is/are true regarding the First Law of Thermodynamics? The law is completely consistent with the Bible's account of creation The law contradicts the Bible The law provides a scientific explanation for matter and energy The Law confirms that matter or energy could not create itself The law shows that the total amount of matter and/or energy in the universe is constant (does not change
Work / time and F.D/T
Which are correct equations for power? work x time work/time time/work F x D x T F x D/T F x T/ D T/ F x D
ft-lb/min j/sec H.P N-m/sec watts
Which are correct power units? lbs/sec ft/min ft-lb ft-lb/min ft-lb-min j-sec j/sec H.P N-m/sec watts
Because it required energy to lift it above the ground
Why does an object above the ground have P.E? because it must be moving because energy is stored in its atoms because it required energy to lift it above the ground because its energy is being stored as heat
force; distance
Work is equal to ______ times _______ power, mass, force, distance
energy
Work is the quantity of ____________ used to move an object
0 joules
_________ joules of work is done when a book weighing 2, 125 N is carried from a desk in one classroom to a desk in another, 25.796 m along a straight hall.
watt
metric unit of power equal to one joule per second
potential energy
stored energy; energy of position
True
t/f Work and energy are measured in the same units
energy
the capacity or ability to do work