torqueCONCEPT .ppt

Yaywymahs

1. BASIC
CONCEPTS
ABOUT TORQUE

2. Torque is a twist
or turn that tends
to produce
rotation. * * *
Applications are
found in many
common tools
around the home
or industry where
it is necessary to
turn, tighten or
loosen devices.

3. Definition of Torque
Torqueis defined as the tendency to
produce a change in rotational motion.
Examples:

7. Torque is Determined by Three Factors:
•The magnitudeof the applied force.
•The directionof the applied force.
•The locationof the applied force.
20 N
Magnitude of force
40 N
The 40-Nforce
produces twice the
torque as does the
20-Nforce.
Each of the 20-N
forces has a different
torque due to the
direction of force. 20 N
Direction of Force
20 N
q
q
20 N 20 N
Location of force
The forces nearer the
end of the wrench
have greater torques.
20 N
20 N

8. Units for Torque
Torque is proportional to the magnitude of
F and to the distance r from the axis. Thus,
a tentativeformula might be:
t= Fr Sin θ Units: Nm
6cm
40 N
t= (40 N)(0.60 m)
= 24.0 Nm, cw
t= 24.0 Nm, cw

9. Direction of Torque
Torque is a vector quantity that has
direction as well as magnitude.
Turning the handle of a
screwdriver clockwiseand
then counterclockwisewill
advance the screw first
inward and then outward.

10. Sign Convention for Torque
By convention, counterclockwise torques are
positive and clockwise torques are negative.
Positivetorque:
Counter-clockwise,
out of page
cw
ccw
Negativetorque:
clockwise, into page

11. Definition of Torque
Torqueis directly proportional to the
amount of force and the length of the
moment arm.(Length or width)
Examples:

12. From this equation, we can
deduced that we can get
LARGE TORQUE even if
there is a SMALL amount of
Force by having MORE
RADIUS
If there is a SHORT amount
of RADIUS, you need to
exert LARGE FORCE

15. How about if you hold the
wrench in the middle? How
much force does it needed.

16. NOTE! (we only needed the half
of the length of the wrench )

18. What have you observed? Which length
needed the greater force? At the edge or
at the middle?

19. The shorter the radius, the greater the
force needed.

20. TRY TO SOLVE
Aboltconnectingthemainandrear
frameofamountainbikerequiresa
torqueof15N⋅mtotighten.Ifyouare
capableofapplying40Nofforcetoa
wrenchinanygivendirection,whatisthe
minimumlengthofthewrenchthatwill
resultintherequiredtorque?

21. TRY TO SOLVE
Solvefortorquegiventhat
awrenchhavealengthof
50cmandmovewitha
forceof6N.

22. TRY TO SOLVE
Findtheforceneededin
ordertohaveatorqueof
16Nmwithanobjectlength
of100cm.