T RQUEGROUP 1

TORQUE

- An influence which tends to change the rotational motion of an object

- effect of a force applied on a body at some distance from the axis of rotation of that body

Unit of measurement: • English = Ft lbs

• SI = Newton meters (Nm)

Formula for Torque

Torque = Force x Lever arm 𝝉 = Fr

The magnitude of the torque is measured by multiplying the perpendicular component of the force applied by the distance between the object’s axis of rotation and the point where the force is applied.

Direction of Torque

Positive torques: Counterclockwise change in rotation( + )

Negative torques: Clockwise change in rotation ( - )

F

F(-) (+)

(+)(-)FClockwise torque Counterclockwise

torque

Data and Observation

Mass, m(kg)

Force, F (N) Lever Arm, s (m)

Moment of Force, (Nm)𝝉+ -

0.04 0.392 0.1 0.0392

0.08 0.784 0.69 0.54096

Center of gravity of the meter stick = 50 cm mark

Percent Error = 1.25%

Mass, m(kg)

Force, F (N) Lever Arm, s (m)

Moment of Force, (Nm)𝝉+ -

0.06 0.588 0.1 0.0588

0.01 0.098 0.2 0.0196

0.14 1.372 0.685 0.93982

Total 0.86222

Percent Error = 2.70%

Weight of the meter stick using:

a. Spring balance = 1.3475N

b. Beam balance = 1.372N

Percentage Difference = 2.45%

Conclusion

On a regular shaped object, the center of gravity may be found on the center point of the object.

By adding different weights on each side, it determines if the center of gravity without the weights is the same center of gravity when you add the weights.

REVIEW QUESTIONS

1. Define the following terms:

a. Torque – a force that produces or tends to produce rotation or torsion.

b. Lever arm (moment arm) – the distance between the point of application of a force to the axis.

c. Equilibrium – the condition of a system where neither its state of motion nor its internal energy state tends to change with time.

d. Center of Gravity – an imaginary point in a body of matter.

e. Center of Mass – the center of gravity of a body when in uniform gravitational field.

2. What two conditions must be satisfied for an object to be in equilibrium?

1st: net force in all directions must be zero2nd: the net torque acting on the object must be zero

4. Three unequal forces act upon a body at a point so that the body is in equilibrium. If the magnitude of two of the forces are doubled, how must the third force be changed to preserve equilibrium?

If the two forces are on the same place where it exerted, the 3rd force should be half of the two doubled forces combined to maintain equilibrium.

3. Describe ways by which an experiment could locate the center of gravity of irregular shaped objects.

A method of locating the center of gravity of an irregularly shaped object is by plumb-line method.

5. What is the relationship between the term “axis of rotation” and

“center of gravity”?The greater the distance from the axis of rotation to

the center of gravity of an object, the greater the torque required to rotate the object.

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