A tunnel under a river is 2.00 km long. (a) At what frequencies can the air in the tunnel resonate? (b) Explain whether it would
1 answer:
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Answer:
R=0.5B+0.5C+2A+D
Explanation:
By the triangular law of vector addition
vector R= vector B- vector D
As A,B,C,D are edges of the parallelogram,
A is parallel to D but opposite in direction.
Therefore
;
;
B is parallel to C and in same direction.
Answer:
Wg is positive and WT negative.
(Letters in options are all wrongly written).
Explanation:
Remember that the work of a force is the internal product between the force and the displacement .
Since the displacement is downwards like the weight, the work done by gravity is positive, while the work done by the tension is negative since it points upwards.