Path of a projectile as seen from another projectile :

(1) Straight

(2) Circular

(3) Hyperbolic

(4) Parabolic

At a certain instant, a particle moving in the \(xy\text-\)plane has a velocity of \(\vec v=(2\hat{i}+3\hat{j})~\text{m/s}\) and an acceleration of \(\vec a=(-3\hat{i}+2\hat{j})~\text{m/s}^2.\) What is the rate of change of the particle’s speed at that instant?
1. \(\sqrt{13}\) m/s²
2. \(-1\) m/s²
3. \(1\) m/s²
4. zero

Which of the following statement/s is/are incorrect regarding the motion in a plane?

A body started moving with an initial velocity of \(4\) m/s along the east and an acceleration \(1\) m/s² along the north. The velocity of the body just after \(4\) s will be?

The radius vector of a particle moving on a circle is given by $\overrightarrow{\mathrm{r}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>\mathrm{AcosBt}\hat{\mathrm{i}}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>\mathrm{AsinBtj}\stackrel{}{^}$ (A and B are constants). The radius of the circle and speed of the particle, respectively, are

1.  A, AB

2.  $\mathrm{A},<mspace\; width="1em"></mspace>\frac{{\mathrm{A}}^2}{\mathrm{B}}$

3.  B, AB

4.  $\mathrm{B},<mspace\; width="1em"></mspace>\frac{{\mathrm{A}}^2}{\mathrm{B}}$

For a particle projected on a horizontal surface, the ratio of range to maximum height is:

($\mathrm{\theta }$ is the angle of projection with respect to horizontal):

(1) 4cot$\mathrm{\theta }$

(2) 4tan$\mathrm{\theta }$

(3) 0.25cot$\mathrm{\theta }$

(4) 0.25sin$\mathrm{\theta }$

Two projectiles, one fired from the surface of the earth with speed 5 m/s and the other fired from the surface of a planet with initial speed 3 m/s with the same angle of the projection, trace identical trajectories. Neglecting friction effect, the value of acceleration due to gravity on the planet is:

(1) 5.9 $\mathrm{m}/{\mathrm{s}}^2$

(2) 3.6 $\mathrm{m}/{\mathrm{s}}^2$

(3) 16.3 $\mathrm{m}/{\mathrm{s}}^2$

(4) 8.5 $\mathrm{m}/{\mathrm{s}}^2$

A projectile is projected from origin of a co-ordinate system with initial velocity of $2\hat{\mathrm{i}}<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>3\hat{\mathrm{j}}$ m/s considering y-axis along vertical. The equation of its trajectory is (take g = 10 $\mathrm{m}/{\mathrm{s}}^2$)

(1) 6y = 4x - 5${\mathrm{x}}^2$

(2) 5y = 6x - 4${\mathrm{x}}^2$

(3) 4y = 6x - 5${\mathrm{x}}^2$

(4) 6y = 5x - 4${\mathrm{x}}^2$

During the downward motion of an oblique projectile from the top point of its trajectory, the radius of curvature of its trajectory will:

(1) Remain constant

(2) Increase

(3) Decrease

(4) May increase or decrease

A particle is thrown obliquely at \(t=0\). The particle has the same K.E. at \(t=5\) seconds and at \(t=9\) seconds. The particle attains maximum altitude at:
1. \(t=6\) s
2. \(t=7\) s
3. \(t=8\) s
4. \(t=14\) s