W Fd Units and Direction Positive and Negative Work When Work 0 Work Work W is the energy transferred to an object when a force acting on the object moves it through a distance W F x d ID: 637081
Download Presentation The PPT/PDF document "Work and Energy Work Done" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Work and Energy
Work DoneW = FdUnits and DirectionPositive and Negative WorkWhen Work = 0Slide2
WorkWork (W) is the
energy transferred to an object when a force acting on the object moves it through a distance W = F x d____________________Slide3
TeachWithFergy Preview File
Please enjoy this preview of your Student Version of the Power Point. Some slides appear blank because they have been removed. Student versions have portions of the text removed which is given in the teacher version and appear as ______
Other slides may have ........... on them, this represents writing that has been removed.
Please note that the Entire Unit Package can also be purchased at a steep discount from my Store. Slide4
Work DoneWork is done when you lift an object
_______Work is done to make a car accelerateSlide5
WorkConsider a situation where you are pulling a bag on wheels at an angle
Θ to the displacement________Slide6
This slide has been removedSlide7
Units and DirectionWork is scalar and has no directionIts units are N
m = J__________ Stop at 3:42Slide8
Positive or Negative WorkIf the force and displacement are in the same direction, work is “+”. If F and d are in opposite directions, work is “-”
Work is positive, negative, or zero, depending on the angle between the force and the displacement. d = rTry an example on your own for eachSlide9
If velocity is constant, isn’t a = 0 and therefore, F = 0 and W = 0?
Whenever you talk about the work done, you must be very careful to specify which force does the work. i.e. if the object is moving at a constant vWfriction= Ff x d _________Wapp = F
app x d
_________Wnet = F
net x d _________
_________
x = +1 m
F
friction
F
ext
= 10 NSlide10
This slide has been removedSlide11
Check Your Understanding2000.0 N of force is applied to a cable used to tow a car as seen below 20.0 km. How much work is being done? Your answer should be in megajoules (1,000,000 J = 1 MJ).Slide12
Check Your UnderstandingA store clerk moved a 4.4-kg box of soap without acceleration along a shelf by pushing it with a horizontal force of magnitude 8.1 N. If the employee did 5.9 J of work on the box, how far did the box move?Slide13
Check Your UnderstandingA toboggan carrying two children (total mass = 85 kg) reaches its maximum speed at the bottom of a hill, and then glides to a stop in
21 m along a horizontal surface. The coefficient of kinetic friction between the toboggan and the snowy surface is 0.11. Draw an FBD of the toboggan when it is moving on the horizontal surface.Determine the magnitude of kinetic friction acting on the toboggan.Slide14
This slide has been removedSlide15
Check Your UnderstandingA bag of groceries of mass 8.1 kg is raised vertically without acceleration from the floor to a countertop, over a distance of 92 cm. Determine
the force needed to raise the bag without accelerationthe work done on the bag of groceries against the force of gravity Slide16
Check Your UnderstandingA student pushes against a large maple tree with a force of magnitude
250 N. How much work does the student do on the tree? Slide17
Check Your UnderstandingA 500-kg meteoroid is travelling through space far from any measurable force of gravity (F approaches 0). If it travels at 10,000 km/h for 100 years, how much work is done on the meteoroid? Slide18
This slide has been removedSlide19
Zero Work Done - SummaryWhen W = 0
________________________________