Im confused with part d A Pendulum bob swings back and forth. At the instant sho
ID: 1624538 • Letter: I
Question
Im confused with part d
A Pendulum bob swings back and forth. At the instant shown, the bob is at one of the turnaround points, labeled A. The other turnaround point, labeled B, and the bob's trajectory (dashed) are shown. a. Choose a point slightly after point A. and label it point C. Draw a vector to represent the velocity of the bob at point C. b. Determine the change-in-velocity vector between points A and C. How would you characterize the direction of delta upsilon as point C is chosen to lie closer and closer to point A? d. Each of the following statements is incorrect. Identify and explain the flaws in reasoning for each statement. i. The acceleration at point A is zero. As point C becomes closer and closer to point A, The change-in-velocity vector becomes smaller and smaller. Eventually, it becomes zero". ii. At point A, the acceleration makes an angle with the tangent to the trajectory that is greater than 0 degree but less than 90 degree because the trajectory is curved and the object is speeding up". e. On the diagram at right, draw vectors at points A and B to indicate the direction of the acceleration at those points.Explanation / Answer
d) (i) acceleration at point A is zero is wrong. at point A acceleration is maximum and given g sin theta, where theta is angle made by string with vertical. rest of statement is right.
(ii) whole statement is wrong because acceleration is always tangential to the curve i.e. angle made by acceleration with tangent to trajectory is always zero.
e) your e part is wrong, as explained above, accelaraton must be tangential to curve i.e. perpendicular to string at A and towards centre(equilibrium point) in the same direction of VA.