The initial speed v, the mass m should be given at the bottom, so that the string reaches a maximum angle is 2.16 m/s.
What is mechanical energy?
The mechanical energy is the sum of kinetic energy and the potential energy of an object at any instant of time.
M.E = KE +PE
Given is a small mass of m = 187 g hangs from a string of length l = 1.21 m. The string reaches a maximum angle of θ = 36.5. The acceleration due to gravity, g = 9.8 m/s²
The vertical height of the point mass h = l- lcosθ
h = 1.21 - (1.21cos 36.5°)
h = 0.2373 m
The conservation of energy principle states that total mechanical energy remains conserved in all situations where there is no external force acting on the system.
Kinetic energy = Potential energy
1/2 mv²= mgh
Substituting the values, we have
1/2 x v² = 9.8 x 0.2373
v = sqrt [2 x9.8 x 0.2373]
v= 2.16 m/s
Thus, the initial speed v the mass m should be given at the bottom, so that the string reaches a maximum angle is 2.16 m/s.
Learn more about mechanical energy.
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