MCQ
A particle has initial velocity $\left( {2\hat i + 3\hat j} \right)$ and acceleration $\left( {0.3\hat i + 0.2\hat j} \right)$. The magnitude of velocity after $10\, seconds$ will be 
  • A
    $5\, units$
  • B
    $9\, units$
  • C
    $9\sqrt 2 \,unit$
  • $5\sqrt 2 \,unit$

Answer

Correct option: D.
$5\sqrt 2 \,unit$
d
$(\overrightarrow{\mathrm{v}})_{\mathrm{att}=10 \mathrm{sec}}=\overrightarrow{\mathrm{u}}+\overrightarrow{\mathrm{a}} \mathrm{t}=(2 \hat{\mathrm{i}}+3 \hat{\mathrm{j}})+(0.3 \hat{\mathrm{i}}+0.2 \hat{\mathrm{j}}) \times 10$

$=5 \hat{\mathrm{i}}+5 \hat{\mathrm{j}}$

$\therefore$ Magnitude $=\sqrt{5^{2}+5^{2}}=5 \sqrt{2} \mathrm{units}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Suppose the medium in the previous question is water. Select the correct option$(s)$ from the list given in that question.
A boy is sitting on the horizontal platform of a joy wheel at a distance of $5 \,m$ from the center. The wheel begins to rotate and when the angular speed exceeds $1 \,rad / s$, the boy just slips. The coefficient of friction between the boy and the wheel is $\left(g=10 \,m / s ^2\right)$
A thin uniform rod of length $L$ and certain mass is kept on a frictionless horizontal table with a massless string of length $L$ fixed to one end (top view is shown in the figure). The other end of the string is pivoted to a point $O$. If a horizontal impulse $P$ is imparted to the rod at a distance $x=L / n$ from the mid-point of the rod (see figure), then the rod and string revolve together around the point $O$, with the rod remaining aligned with the string. In such a case, the value of $n$ is. . . . . . 
A ball of mass $0.2 \ kg$ rests on a vertical post of height $5 m$. A bullet of mass $0.01 \ kg$, traveling with a velocity $V / s$ in a horizontal direction, hits the centre of the ball. After the collision, the ball and bullet travel independently. The ball hits the ground at a distance of $20 \ m$ and the bullet at a distance of $100 \ m$ from the foot of the post. The initial velocity $V$ of the bullet is
The magnitude of potential energy per unit mass of an object at the surface of earth is $E$, then the escape velocity of the object is ..........
A particle has an initial velocity of ($3\hat i + 4\hat j)\;ms^{-1}$ and an acceleration of $(0.4\hat i + 0.3\hat j)\;ms^{-1}$ Its speed after $10\;s$ is:
The dimensional formula for Planck's constant $(h)$ is
Consider a circle of radius $42\  cm$. An insect crawls with uniform speed of $1.3\  cm/s$ along the chord $AB$ then along the circular arc $BCD$ to reach point $D$ and then following cord $DA$ to reach finally $A$. Time spend by the insect to crawl from $A$ to $A$ is closest to    ......... $\sec$
For a given angle of the projectile if the initial velocity is doubled the range of the projectile becomes
The equation $y = 0.15\sin 5x\cos 300t$, describes a stationary wave. The wavelength of the stationary wave is .... $m$