Physics 1st Paper CQ-Barishal Board-2021

1. Notice the following stem where BA and BC are two inclined plane. Friction force on $\mathrm{BA}$ is $1.5 \mathrm{Nkg}^{-1}$ and on $\mathrm{BC}$ is $1 \mathrm{Nkg}^{-1}$. A metallic sphere of mass $3 \mathrm{~kg}$ is placed at $B$.

2. In the following figure a spring of negligible mass is placed on a smooth horizontal table. Its one end is tied with a rigid support and the other end is connected to a body of mass $3.5 \mathrm{~kg}$. A $24 \mathrm{~N}$ restoring force acts on the body when it is displaced 3 from the equilibrium.

3. Three vectors are given below:

$\begin{array}{l} \vec{A}=2 \hat{i}+3 \hat{j}+4 \hat{k} \\ \vec{B}=5 \hat{i}-\hat{j}+6 \hat{k} \\ \vec{C}=4 \hat{i}+2 \hat{j}-3 \hat{k} \end{array}$

4. Notice the following stem where $A(3,3,1)$ and $B(4,-5$, 1) are two points:

5. Karim lifted a body of mass $400 \mathrm{gm}$ from $\mathrm{M}$ to $\mathrm{A}$ applying $11.76 \mathrm{~J}$ kinetic energy making an angle $30^{\circ}$ with the horizontal. Then the body was moved to point B at a distance of $2 \mathrm{~m}$ by applying more force. Again he brought the body to the point $\mathrm{A}$ and let it fall along the inclined plane AM. force is

[Frictional negligible; $\mathrm{g}=9.8 \mathrm{~ms}^{-2}$.]

Here, $\mathrm{MN}=\mathrm{ON}=\mathrm{OP}=\mathrm{PQ}=\mathrm{QR}=\mathrm{AR}$.