1) A uniform 3.0-m plank weighing 150 N is suspended by vertical ropes at either
ID: 1272270 • Letter: 1
Question
1) A uniform 3.0-m plank weighing 150 N is suspended by vertical ropes at either end. A 410-N child stands 0.80 m from the left end of the plank. By summing the torques about an axis passing through the right end of the plank, determine the tension in the rope holding the left end of the plank.
The tension is _____ N
2) A thin rod is pivoted about its center. The rod's mass is 5.0 kg, and its moment of inertia is 5.4 kg m2. What is the length of the rod?
The length is m
3) A wheel accelerates from rest, making 74 complete revolutions in 6.2s. What is the angular speed of the wheel at the end of this interval, assuming its angular accelerarion is constant?
The final angular speed is rad/s
Explanation / Answer
1. T= rFsin theta
T= 1.5*150 +410*2.2 =1,127 N-m (center of mass of plank is 1.5M from axis)
2. I= 1/12 ML^2 (for a thin rod)
5.4= 1/12*5 L^2
L= 3.6 m
3. 74 revolutions is 2pi*74= 74.99 r/s average speed.
Since acceleration was constant 74.99= 1/2 final speed
Final speed 150 rad/s.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.