# Two forces $P$ and $Q$, of magnitude $2 F$ and $3 F$, respectively, are at an angle $\theta$ with each other. If the force $Q$ is doubled, then their resultant also gets doubled. Then, the angle $\theta$ is:

Question:

Two forces $P$ and $Q$, of magnitude $2 F$ and $3 F$, respectively, are at an angle $\theta$ with each other. If the force $Q$ is doubled, then their resultant also gets doubled. Then, the angle $\theta$ is:

1. $120^{\circ}$

2. $60^{\circ}$

3. $90^{\circ}$

4. $30^{\circ}$

JEE Main Previous Year Single Correct Question of JEE Main from Physics Motion in a Plane chapter.

JEE Main Previous Year 10 Jan. 2019 II

Correct Option: 1

Solution:

### Related Questions

• Let $\left|\overrightarrow{A_{1}}\right|=3,\left|\overrightarrow{A_{2}}\right|=5$ and $\left|\overrightarrow{A_{1}}+\overrightarrow{A_{2}}\right|=5$. The value of $\left(2 \overrightarrow{\mathrm{A}_{1}}+3 \overrightarrow{\mathrm{A}_{2}}\right) \cdot\left(3 \overrightarrow{\mathrm{A}_{1}}-2 \overrightarrow{\mathrm{A}_{2}}\right)$ is :

View Solution

• In the cube of side ‘a’ shown in the figure, the vector from the central point of the face $\mathrm{ABOD}$ to the central point of the face BEFO will be:

View Solution

• Two vectors $\vec{A}$ and $\vec{B}$ have equal magnitudes. The magnitude of $(\overrightarrow{\mathrm{A}}+\overrightarrow{\mathrm{B}})$ is ‘ $n$ ‘ times the magnitude of $(\overrightarrow{\mathrm{A}}-\overrightarrow{\mathrm{B}})$.

The angle between $\vec{A}$ and $\vec{B}$ is:

View Solution

• Let $\overrightarrow{\mathrm{A}}=(\hat{\mathrm{i}}+\hat{\mathrm{j}})$ and $\overrightarrow{\mathrm{B}}=(\hat{\mathrm{i}}-\hat{\mathrm{j}})$. The magnitude of a coplanar vector $\overrightarrow{\mathrm{C}}$ such that $\overrightarrow{\mathrm{A}} \cdot \overrightarrow{\mathrm{C}}=\overrightarrow{\mathrm{B}} \cdot \overrightarrow{\mathrm{C}}=\overrightarrow{\mathrm{A}} \cdot \overrightarrow{\mathrm{B}}$ is given by

View Solution

• A vector $\vec{A}$ is rotated by a small angle $\Delta \theta \operatorname{radian}(\Delta \theta<<1)$

to get a new vector $\vec{B}$. In that case $|\vec{B}-\vec{A}|$ is :

View Solution

• If $\vec{A} \times \vec{B}=\vec{B} \times \vec{A}$, then the angle between $\mathrm{A}$ and $\mathrm{B}$ is

View Solution

• A balloon is moving up in air vertically above a point A on the ground. When it is at a height $h_{1}$, a girl standing at a distance $d$ (point B) from A (see figure) sees it at an angle $45^{\circ}$ with respect to the vertical. When the balloon climbs up a further height $h_{2}$, it is seen at an angle $60^{\circ}$ with respect to the vertical if the girl moves further by a distance $2.464 d$ (point $\mathrm{C}$ ). Then the height $h_{2}$ is (given $\tan 30^{\circ}=0.5774$ ):

View Solution

• Starting from the origin at time $t=0$, with initial velocity

$5 \hat{j} \mathrm{~ms}^{-1}$, a particle moves in the $x-y$ plane with a constant acceleration of $(10 \hat{i}+4 \hat{j}) \mathrm{ms}^{-2}$. At time $t$, its coordiantes are $\left(20 \mathrm{~m}, y_{0} \mathrm{~m}\right)$. The values of $t$ and $y_{0}$ are, respectively:

View Solution

• The position vector of a particle changes with time according to the relation $\vec{r}(\mathrm{t})=15 \mathrm{t}^{2} \hat{i}+\left(4-20 \mathrm{t}^{2}\right) \hat{j}$. What is the magnitude of the acceleration at $t=1 ?$

View Solution

• A particle moves from the point $(2.0 \hat{i}+4.0 \hat{j}) \mathrm{m}$, at $\mathrm{t}=0$, with an initial velocity $(5.0 \hat{i}+4.0 \hat{j}) \mathrm{ms}^{-1}$. It is acted upon by a constant force which produces a constant acceleration $(4.0 \hat{i}+4.0 \hat{j}) \mathrm{ms}^{-2}$. What is the distance of the particle from the origin at time $2 \mathrm{~s}$ ?

View Solution

error: Content is protected !!