Physics 1st Paper CQ-Chittagong Board-2017

1. Three wires of equal length A, B and C are attached with a sonometer. And three weights of 200,225 and $250 \mathrm{~N}$ are attached with them respectively. As the wire A was sounded it produced a sound of $100 \mathrm{~Hz}$. An experiment was done to see if there is a bit produced when two wires are sounded together.

2. A particle that is moving in a simple harmonic motion weighs $100 \mathrm{gm}$. Maximum amplitude is $10 \mathrm{~cm}$. The time required to reach maximum amplitude from equilibrium is $0.5 \mathrm{~s}$

3. A group of scientists sent a $100 \mathrm{~kg}$ artificial satellite at $3.6 \times 10^{4} \mathrm{~km}$ height and gave it $3.1 \mathrm{~km} / \mathrm{s}$ linear velocity thus attempted to make a moon like satellite. Mass and radius of earth are respectively 81 and 16 times of moon's mass and radius. Distance from earth to moon is $3 \times 10^{5} \mathrm{~km}$. Gravitational acceleration on earth is $9.8 \mathrm{~ms}^{-2}$, Gravitational constant is $6.673 \times 10^{-11} \mathrm{Nm}^{2} \mathrm{~kg}^{-2}$.

4. According to the diagram, a river is $31 \mathrm{~km}$ wide. Two boats started from the same point $A$ at same speed to cross the river. One is going along $A B$ and another one along AC. First one reached point $C$ after crossing the river though the second one reached point D. Velocity of current was $9 \mathrm{~km} \mathrm{~h}^{-1}$.

5. In the chart below velocity and displacement of a $10 \mathrm{gm}$ moving particle are shown: