A mass of 2.0 kg is put on a flat pan attached to a vertical spring fixed on the ground as shown in the figure. The mass of the spring and the pan is negligible. When pressed slightly and released the mass executes a simple harmonic motion. The spring constant is 200 N/m. What should be the minimum amplitude of the motion so that the mass gets detached from the pan (take g = 10 m/s2). [figure]
- 10.0 cm
- any value less than 12.0 cm
- 4.0 cm
- 8.0 cm
Answer
(1) 10.0 cm
Solution
The mass leaves the pan when the normal reaction becomes zero, i.e., at the highest point the downward acceleration of the pan equals g.
Maximum acceleration in SHM = 2 A = kmA
kmA = g
A = mgk = 2.0 10200
= 0.1 m = 10.0 cm
Answer: (1)