Home / IBDP Physics- C.1 Simple harmonic motion- IB Style Questions For HL Paper 1A

IBDP Physics- C.1 Simple harmonic motion- IB Style Questions For HL Paper 1A -FA 2025

Question

A mass-spring system oscillates with period \( T_1 \).
 
 
 
 
 
 
 
An identical spring is added in parallel, keeping the mass the same.
 
 
 
 
 
 
 
The new period is \( T_2 \). What is \( \frac{T_2}{T_1} \)?
(A) \( \frac{1}{2} \)
(B) \( \frac{1}{\sqrt{2}} \)
(C) \( \sqrt{2} \)
(D) 2
▶️ Answer/Explanation
Detailed solution

Time period \( T = 2\pi \sqrt{\frac{m}{k}} \)
For one spring: \( T_1 = 2\pi \sqrt{\frac{m}{k}} \)
For identical springs in parallel: \( k_{eff} = 2k \)
So \( T_2 = 2\pi \sqrt{\frac{m}{2k}} = \frac{T_1}{\sqrt{2}} \)
Therefore \( \frac{T_2}{T_1} = \frac{1}{\sqrt{2}} \)
Answer: (B)

Question

A simple pendulum oscillates with frequency \(f\). The length of the pendulum is halved.
What is the new frequency of the pendulum?
(A) \(2f\)
(B) \(\sqrt{2}f\)
(C) \(\dfrac{f}{\sqrt{2}}\)
(D) \(\dfrac{f}{2}\)
▶️ Answer/Explanation
Detailed solution

The frequency of a simple pendulum is given by \( f = \dfrac{1}{2\pi}\sqrt{\dfrac{g}{L}} \).

If the length is halved, \( L \rightarrow \dfrac{L}{2} \), the new frequency is
\( f’ = \dfrac{1}{2\pi}\sqrt{\dfrac{g}{L/2}} = \dfrac{1}{2\pi}\sqrt{\dfrac{2g}{L}} \).

Comparing with the original frequency,
\( \dfrac{f’}{f} = \sqrt{2} \).

Hence, the new frequency is \( \sqrt{2}f \).

Answer: (B)

Question

Which graph represents the variation with displacement of the potential energy \(P\) and the total energy \(T\) of a system undergoing simple harmonic motion (SHM)?
C.1 Simple harmonic motion HL Paper 1
▶️ Answer/Explanation
Detailed solution

In simple harmonic motion, the potential energy varies with the square of the displacement from the equilibrium position, producing a parabolic curve. The total energy of the system remains constant and is represented by a horizontal line.

Among the given graphs, only option (B) correctly shows a parabolic variation of potential energy with displacement and a constant total energy.

Answer: (B)

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