Page 5 - 9-phy-2 Kinematics
P. 5
Find the value of g by free fall method.
2.2
Date ________________
A metal bob and a bar pendulum are tied together with the help of a thread as
shown in Fig. 2.2.1. When the thread is burnt, the bob and the bar are released
simultaneously. The bob falls freely from rest, such that the bar makes exactly a
quarter of an oscillation during the time of free fall. Thus, the time of free fall is
equal to one fourth of the time period T. We can find the value of g by finding the
time taken by the bob as it falls through height 'h' from rest to hit the bar. The
formula for finding the value of g is
h = vi t + 1 gt 2
2
as the bob falls from rest, so its initial velocity vi= 0
then g = 2h as t = T 32h
t2 4 , g= T2
Free fall apparatus, metre rod, stop watch, string, candle, metallic bob, match box.
P
Pulley
bob N Q
Metre bar W
Pulley
Board String
M R
Leveling
screw
Fig 2.2.1
16
2.2
Date ________________
A metal bob and a bar pendulum are tied together with the help of a thread as
shown in Fig. 2.2.1. When the thread is burnt, the bob and the bar are released
simultaneously. The bob falls freely from rest, such that the bar makes exactly a
quarter of an oscillation during the time of free fall. Thus, the time of free fall is
equal to one fourth of the time period T. We can find the value of g by finding the
time taken by the bob as it falls through height 'h' from rest to hit the bar. The
formula for finding the value of g is
h = vi t + 1 gt 2
2
as the bob falls from rest, so its initial velocity vi= 0
then g = 2h as t = T 32h
t2 4 , g= T2
Free fall apparatus, metre rod, stop watch, string, candle, metallic bob, match box.
P
Pulley
bob N Q
Metre bar W
Pulley
Board String
M R
Leveling
screw
Fig 2.2.1
16
