work and the joule Flashcards
Define work done
The work done, is the product of the force and the distance moved by the force in the direction of movement.
What is the equations of work done
w = f x s
power x time = work done
what is the link between energy transferred and work done
they are the same
is work a vector or scalar quantity and why
its a scalar quantity because it has a magnitude but no direction.
what can work done be though of as
amount of energy transferred from one form to another
a man pushes a shopping trolley with a horizontal force of 28N, moving a distance of 12m.
A) how much work did he do on the trolley if there was no friction
B) How much work did he do on the trolley if the frictional force was 8N
C) what is the meaning of the subtraction of the work done in part a and b.
A) 336J
B) 240J
c) 96J was done in overcoming the frictional forces and this work was not done on the trolley
what is the SI unit of work done
J ie.joule
What is the equivalent of 1 joule in newton terms
Newtonmetre
Nm
For vertical motion what is the significance of Force (F)
in the equation
W = FS
F = mg
force here is the weight of the object
an object of mass 34kg is raised from the ground to a shelf 7.5 metres above the ground. How much work has been done?
GIVE STEPS
W= fs
W= mg x distance in direction of force
W = 34g x 7.5
W= 2500J
what is the equation for work done when force applied at an angle
w = Fs Cos theta