Walker4e
What is the torque about the elbow caused by the tension T?
A. L T sin 40.0°
B. L T cos 40.0°
C. L T tan 40.0°
D. L T
Answer
Knight2 stt 12.3
Rank the following torques from smallest to largest. The rods all have the same length and each pivot at the dot.
A. τa < τb < τc < τd < τe
B. τc < τe < τb < τa < τd
C. τc < τb < τa = τd < τe
D. τa = τb = τc < τd < τe
Answer
PSE10 Ex 11.01mod
Two vectors lying in the xy plane are given by the equations A = 3î + 2ĵ and B = −4î + ĵ. Calculate
the vector product A × B.
A. −12î + 2ĵ
B. 3î − 8ĵ
C. −5k̂
D. 11k̂
Answer
PoP5 10.25
Given
and
calculate
the vector product
A. 
B. 
C. 
D. 
Answer
answer
A. L T sin 40.0°
Only the component of the tension T that is perpendicular
to the moment arm L will produce a torque. That component is Ty, and it
is the side opposite to the angle, so Ty = Tsin 40°.
answer
C. τc < τb < τa = τd < τe
All the depicted torques are counterclockwise and therefore are positive in sign.
τa = rF sin 90° = rF
τb = ½rF sin 90° = ½rF
τc = rF sin 0° = 0
τd = ½r(2F)sin 90° = rF
τe = r(2F)sin 45° = √2 rF
answer
D. 11k̂
answer
D.
