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Please help!
You release a pendulum of mass 1 kg from a height of 0.75 m.
A. If there is no air resistance, how fast is the pendulum going when it reaches the bottom?
B. If the pendulum loses 18% of its initial energy by the time it reaches the bottom, how fast is it going when it reaches the bottom?
C. If the pendulum loses another 7% of its remaining energy by the time it reaches the other side, how high does it go?
D. After a few minutes, the pendulum is no longer swinging at all explain why this happens, in terms of energy.

Respuesta :

(A) The speed of the pendulum when it reaches the bottom is 3.83 m/s.

(B) The speed of the  pendulum when it reaches the bottom after losing 18% of its energy is 3.47 m/s.

(C) The height reached by the pendulum after losing another 7% of its energy is 0.57 m.

(D) When the pendulum stops swinging, it has used all its energy to overcome frictional force of air.

Speed of the pendulum when it reaches the bottom

Apply the principle of conservation of energy;

K.E = P.E

¹/₂mv² = mgh

v² = 2gh

v = √2gh

v = √(2 x 9.8 x 0.75)

v = 3.83 m/s

Speed pendulum after losing 18% of the its initial energy

K.E = (100 -  18)P.E

¹/₂mv² = 0.82mgh

V = √(0.82 x 2gh)

v = √(0.82 x 2 x 9.8 x 0.75)

v = 3.47 m/s

Height reached when its looses another 7%

K.E = 0.5(1)(3.47)² = 6.02 J

When it losses 7% = 6.02 - (0.07 x 6.02) = 5.598 J

Height reached:

mgh = 5.598

h = 5.598/mg

h = 5.598/(1 x 9.8)

h = 0.57 m

Final energy of the pendulum

When the pendulum stops swinging, it has used all its energy to overcome frictional force of air.

Thus, the speed of the pendulum when it reaches the bottom is 3.83 m/s.

The speed of the  pendulum when it reaches the bottom after losing 18% of its energy is 3.47 m/s.

The height reached by the pendulum after losing another 7% of its energy is 0.57 m.

Learn more about speed of pendulum here: https://brainly.com/question/13655641

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