January 21, 2003 MJM PH 112 Name ______________________________ Box # ____
Torque = r x F |torque| = rF sin (r is the distance from reference pt to point of application of F)
Torque = Fl, where l is the 'lever arm' of the force with respect to the reference point (p. 295)
7.0 N
A 40o B
3.5 m 2.5 m
Calculate the 'lever arm' for the
7.0 N force with respect to point A
Calculate the torque with respect to
point A from the 7.0 N force.
Draw point C on the sketch above such that the torque with respect to C is zero.
Find the torque of the 7.0 N force
with respect to point B.
Angular momentum = L = I for a solid body which is rotating (it's the rotational analog of p = mv )
For a point particle travelling through space L = r x p = r x (mv),
where r is the vector from the reference point to the particle.
A particle of mass 2.0 kg is travelling to the right at a speed of 1.5 m/s.
Draw points A and B on the sketch so that L with respect to either of these points is zero.
Indicate whatever numerical values are needed, if any.
Draw points C and D on the sketch so LC and LD = 6.0 kg m2/s coming out of the page.
Indicate whatever numerical values are needed, if any.
