گردشی حرکت اور سادہ ہارمونی حرکت

Written by Dr. Hamza Farooq (Physics)

ایم ڈی کیٹ · طبیعیات · 8 سوالات

نام: ____________________ تاریخ: ____________

In simple harmonic motion, the acceleration is always:
- A Proportional to the displacement and directed towards the mean position
- B Proportional to the velocity
- C Zero at the extremes
- D Constant
A 0.5 kg mass hangs on a spring of constant 50 N/m and oscillates. What is the time period? (Take pi = 3.14)
- A 0.63 s
- B 6.3 s
- C 0.063 s
- D 1.0 s
In SHM, the speed of the body is greatest at the:
- A Mean position
- B It is constant
- C Extreme position
- D Halfway between mean and extreme
What is the angular velocity of a wheel turning at 60 revolutions per minute?
- A 377 rad/s
- B 60 rad/s
- C 6.28 rad/s
- D 3.14 rad/s
A torque acts on a body with moment of inertia 2 kg m² and gives it an angular acceleration of 3 rad/s². What is the torque?
- A 1.5 N m
- B 5 N m
- C 6 N m
- D 9 N m
What is the rotational kinetic energy of a body with I = 2 kg m² and angular velocity 3 rad/s?
- A 9 J
- B 6 J
- C 12 J
- D 18 J
The total energy of a body in SHM, ignoring damping, is:
- A Constant
- B Largest at the mean position only
- C Increasing with time
- D Zero
An oscillator has a frequency of 5 Hz. What is its time period?
- A 2 s
- B 5 s
- C 0.5 s
- D 0.2 s

جوابی کلید

1. A, 2. A, 3. A, 4. C, 5. C, 6. A, 7. A, 8. D

The defining feature of SHM is a = -(omega squared) x displacement, a restoring acceleration towards the equilibrium position.
T = 2 pi sqrt(m / k) = 2 x 3.14 x sqrt(0.01) = 0.628 s, about 0.63 s.
All the energy is kinetic at the mean position, so the speed there is a maximum.
60 rev/min is 1 rev/s, which is 2 pi, about 6.28 rad/s.
Torque = I x alpha = 2 x 3 = 6 N m.
KE = 1/2 I w² = 0.5 x 2 x 9 = 9 J.
Energy keeps changing between kinetic and potential forms, but the total stays constant.
T = 1 / f = 1 / 5 = 0.2 s.