Page 6 - 9-phy-2 Kinematics

ΠTie one end of the string, passing over two pulleys, with the bob and the

other end with the hook near the end of the bar.

Note the initial position (h1) of the centre of the bob. The initial position

of the bob is kept a few centimeters lower from the hinge of the

oscillating bar.

Ž Blacken the bob with soot of a candle, and remove any mark already

present on the side of the bar.

 Release the bob by burning thread between the

two pulleys.

 Note the position (h2) of black mark caused by Why is scissors or blade

DO YOU KNOW? the bob when it strikes the bar. not used to cut the string?

A satellite orbiting the ‘ Repeat the above procedure two times more.
earth is infact a freely ’
falling body. Set the bar to oscillate and note the time for 10
“
oscillations with the help of a stop watch.

Repeat this step three times and find average time to.

Calculate the time period T.

No. of obs. Initial position of bob Position of Black mark height
1
(h1) (h2) h= h2 – h1
(cm) (cm) (cm)

2

3

Time for 10 vibrations !
(i) ----------------
(ii) --------------- • The oscillating bar
(iii) ---------------- should be made
vertical by leveling
Mean time t0 = ------------ s. screws at the base.

Time period of the bob = T = t ° ------------ s. • The bar should move
10 freely without
touching the board.
Time for free fall = t = T
4 ---------- s. • The amplitude of
oscillation should be
small.

Value of g = 2h = ............. cm s-2
t2

g = ............. cm s-2

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