Two blocks of mass m = 13.5 kg each are fastened to the ceiling of an elevator, as seen in the figure at http://i1309.photobucket.com/albums/s627/zalud1ke/serw0426_zps74682286.gif
A.The elevator accelerates upward at a = 1.97 m/s2. Find the tension in the bottom rope.
B. Find the tension in the top rope.
A.The elevator accelerates upward at a = 1.97 m/s2. Find the tension in the bottom rope.
B. Find the tension in the top rope.
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Let me show you the normal way to show exponents here.
1.97 m/s^2 where the ^ is shift+6.
A. The bottom block accelerates up at 1.97 m/s^2. Therefore it has a net force on it given by
Fnet = m*a = 13.5 kg*1.97 m/s^2 = 26.6 N
The net force consists of the block's weight + the tension in the rope (I'll let up be the positive direction).
Fnet = -m*g + T = 13.5 kg*(-9.8 m/s^2) + T = -132.3 N + T
We said Fnet was 26.6 N above, so
26.6 N = -132.3 N + T
T = 158.9 N
B. This is the same except the mass that the tension in the upper rope has to accelerate is both blocks. You could just consider it one 27 kg block hanging from the rope tied to the ceiling. The rope can't tell the difference.
1.97 m/s^2 where the ^ is shift+6.
A. The bottom block accelerates up at 1.97 m/s^2. Therefore it has a net force on it given by
Fnet = m*a = 13.5 kg*1.97 m/s^2 = 26.6 N
The net force consists of the block's weight + the tension in the rope (I'll let up be the positive direction).
Fnet = -m*g + T = 13.5 kg*(-9.8 m/s^2) + T = -132.3 N + T
We said Fnet was 26.6 N above, so
26.6 N = -132.3 N + T
T = 158.9 N
B. This is the same except the mass that the tension in the upper rope has to accelerate is both blocks. You could just consider it one 27 kg block hanging from the rope tied to the ceiling. The rope can't tell the difference.