Concept explainers
A simple pendulum (a mass swinging at the end of a string) swings back and forth in a circular arc. What is the direction of the acceleration of the mass when it is at the ends of the swing? At the midpoint? In each case, explain how you obtained your answer.
The direction of acceleration of mass when it is at the end of swing and at midpoint.
Answer to Problem 3.1DQ
There is zero acceleration at end point while direction of tangential acceleration changes from zero.
Explanation of Solution
When the mass reaches at end points the tangential force acts on the mass towards the mean position which results the net acceleration acts towards midpoint.
When the mass reaches at the midpoint, the gravitational force balances the tension in the string. So the resultant force on the mass is zero which results the net acceleration becomes zero.
Figure 1
Conclusion: There is zero acceleration at end point while direction of tangential acceleration changes from zero.
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