12 Physics Experiment 4. Spring mass oscillator

 Spring mass oscillator

Suspend a light Pan from the lower end of the string suspended vertically from a rigid support. Add a suitable mass

M in the pan so that the spring is stretched to about triple of the unstretched length under its own weight. Take the

position of a pointer as Zero. Note the position of pointer for any one value of mass in the pan(m) less than M and

one value of mass m more than M find extension (x ). Hence determine force constants of the spring.

Aim: To find the force constant and effective mass of helical spring

Apparatus: Light helical spring, clamp, pointer meter scale, hanger, slotted weights, stop watch etc.

Diagram:-

Observation table :

Calculation: 1) x1 = 3.5 cm , 

F1= 50 x 980 = 49000

 2) x2 = 3 cm , F2 = 50 x 980 = 49000

MCQ Questions (with answers)

1. In the experiment, the force constant of the spring is determined using which physical law?

A. Newton’s First Law
B. Pascal’s Law
C. Hooke’s law
D. Archimedes’ Principle
Answer: C

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2. The force constant $k$ of the spring is defined as:

A. $k = \frac{x}{F}$
B. $k = \frac{F}{x}$
C. $k=Fx\mathrm{<br>}\mathrm{<br>}\mathrm{<br>}\mathrm{<br>}\mathrm{<br>}\mathrm{<br>}$ 

D. $k = \frac{1}{Fx}$
Answer: B

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3. In this experiment, the extension $\mathrm{<strong\; data-end="768"\; data-start="692"><span\; class="katex"><span\; aria-hidden="true"\; class="katex-html"><span\; class="base"><span\; class="mord\; mathnormal">x</span></span></span></span>\; in\; the\; spring\; is\; caused\; by:</strong>}$

A. Magnetic force
B. Electric force
C. Gravitational force of added masses
D. Air resistance
Answer: C

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4. The mass in the pan is adjusted so that the spring initially stretches to about three times its unstretched length. This helps to:

A. Increase accuracy due to larger measurable extension
B. Decrease the length of the spring
C. Reduce the weight of the system
D. Avoid using the pointer
Answer: A

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5. The extension $x$ is measured as the difference between:

A. Final and initial mass
B. Final and initial length of spring
C. Weight and mass
D. Displacement and velocity
Answer: B

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6. If a mass $m$ is added and the extension becomes $x$, the force applied on the spring is:

A. $mg$
B. $m + g$
C. $\frac{m}{g}$
D. $\frac{g}{m}$
Answer: A

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7. A graph between force (mg) and extension $\mathrm{<strong\; data-end="1724"\; data-start="1645"><span\; class="katex"><span\; aria-hidden="true"\; class="katex-html"><span\; class="base"><span\; class="mord\; mathnormal">x</span></span></span></span>\; for\; an\; ideal\; spring\; is:</strong>}$

A. A parabola
B. A straight line
C. A curve bending downward
D. A hyperbola
Answer: B

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8. The slope of the graph of applied force vs. extension gives:

A. Mass of the pan
B. Velocity of oscillation
C. Force constant $k$
D. Time period
Answer: C

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9. If the extension doubles when mass is doubled, the spring obeys:

A. No physical law
B. Hooke’s law
C. Boyle’s law
D. Newton’s third law only
Answer: B

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10. The SI unit of the spring constant $k$ is:

A. kg
B. N
C. N/m
D. m/N
Answer: C