A uniform rod of length 2m and mass 500g is suspended from one end. It is displaced through 60° from
the vertical and released. What is the KE of the rod while passing through the mean position
1) 1J
2)2J
3) 2.5J
4) 5J
Answers
Explanation:
this is the explanation cg= centre of gravity. and classical work energy theorem is also applied hope it helps
The correct option to the above question is (4) which is 5 J.
Given: Length of rod = 2 m
Mass of rod = 500 grams
Displaced through an angle of 60°
To find The kinetic energy of the rod while passing through the mean position.
Solution:
From the law of conservation of energy,
Change in potential energy is equal to Kinetic energy at the vertical position.
Since the rod is displaced from one end, therefore the length will be 2 m.
Potential energy will be = mglCosθ
Where m is the mass of the rod, g is the acceleration due to gravity, l is the length and θ is the angle through which it is displaced.
Putting the value into the equation we get,
P.E = 500/1000 × 10 × 2 ×1/2
= 5 J
This potential energy will be the kinetic energy of the rod when it will move through the mean position.
Therefore, the kinetic energy is equal to 5 J, and the correct option is (4).