Question

A simple pendulum is being used to determine the value of gravitational acceleration g at a certain place. The length of the pendulum is 25.0 cm and a stop watch with 1s resolution measures the time taken for 40 oscillations to be 50 s. The accuracy in g is :

(1) 3.40%

(2) 5.40%

(3) 4.40%

(4) 2.40%

Answer 1

Answer is (3) 4.40%

Comments

Time for 40 oscillations is 50s, so why T is not taken to be 5/4??

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The time period is 5/4 only but for finding the accuracy T = total time and change in time = resolution. The final answer remains same at another value of T also because then even resolution changes accordingly.

Answer 2

Answer is (3) 4.40%

 = 4.40 %