گردش اور ارتعاش

Written by Dr. Hamza Farooq (Physics)

ای کیٹ · طبیعیات · 5 سوالات

نام: ____________________ تاریخ: ____________

What is the moment of inertia of a uniform solid disc of mass M and radius R about its central axis?
- A MR²
- B MR² / 2
- C MR² / 3
- D 2MR² / 5
A simple pendulum is 2.5 m long. What is its period? (g = 10 m/s²; take pi = 3.14)
- A 3.14 s
- B 1.57 s
- C 0.5 s
- D 6.28 s
A wheel has a moment of inertia of 0.5 kg m² and spins at 4 rad/s. What is its angular momentum?
- A 2 kg m²/s
- B 8 kg m²/s
- C 16 kg m²/s
- D 0.5 kg m²/s
A 2 kg ball moves in a circle of radius 1.5 m at a constant speed of 3 m/s. What centripetal force acts on it?
- A 9 N
- B 6 N
- C 18 N
- D 12 N
Resonance occurs when the driving frequency is:
- A Much larger than the natural frequency
- B Equal to the natural frequency
- C Half the natural frequency
- D Zero

جوابی کلید

1. B, 2. A, 3. A, 4. D, 5. B

For a solid disc about its axis, I = 1/2 MR².
T = 2 pi sqrt(L / g) = 2 x 3.14 x sqrt(0.25) = 2 x 3.14 x 0.5 = 3.14 s.
L = I x omega = 0.5 x 4 = 2 kg m²/s.
F = mv² / r = 2 x 9 / 1.5 = 12 N.
When the driving frequency matches the natural frequency, energy is transferred most efficiently and the amplitude is largest.