A particle starting from the point \((1,2)\) moves in a straight line in the \(XY\)-plane. Its coordinates at a later time are \((2,3).\) The path of the particle makes what angle with the \(x\)-axis?
1. \(30^\circ\)
2. \(45^\circ\)
3. \(60^\circ\)
4. data is insufficient
| 1. | \(4\sqrt2~\text{ms}^{-1},45^\circ\) | 2. | \(4\sqrt2~\text{ms}^{-1},60^\circ\) |
| 3. | \(3\sqrt2~\text{ms}^{-1},30^\circ\) | 4. | \(3\sqrt2~\text{ms}^{-1},45^\circ\) |
The \(x\) and \(y\) coordinates of the particle at any time are \(x=5 t-2 t^2\) and \({y}=10{t}\) respectively, where \(x\) and \(y\) are in meters and \(\mathrm{t}\) in seconds. The acceleration of the particle at \(\mathrm{t}=2\) s is:
| 1. | \(5\hat{i}~\text{m/s}^2\) | 2. | \(-4\hat{i}~\text{m/s}^2\) |
| 3. | \(-8\hat{j}~\text{m/s}^2\) | 4. | \(0\) |
A particle has an initial velocity (\(2\hat{i}+3\hat{j}\)) and an acceleration (\(0.3\hat{i}+0.2\hat{j}\)). The magnitude of velocity after \(10\) s will be:
1. \(9 \sqrt{2} ~\text{units} \)
2. \(5 \sqrt{2} ~\text{units} \)
3. \(5 ~\text{units} \)
4. \(9~\text{units} \)
The velocity of a projectile at the initial point \(A\) is \(2\hat i+3\hat j~\text{m/s}.\) Its velocity (in m/s) at the point \(B\) is:
| 1. | \(-2\hat i+3\hat j~\) | 2. | \(2\hat i-3\hat j~\) |
| 3. | \(2\hat i+3\hat j~\) | 4. | \(-2\hat i-3\hat j~\) |
| 1. | The velocity and acceleration both are parallel to \(\vec{r }.\) |
| 2. | The velocity is perpendicular to \(\vec{r }\) and acceleration is directed towards to origin. |
| 3. | The velocity is parallel to \(\vec{r }\) and acceleration is directed away from the origin. |
| 4. | The velocity and acceleration both are perpendicular to \(\vec{r}.\) |
A man standing on a road holds his umbrella at \(30^{\circ}\) with the vertical to keep the rain away. He throws the umbrella and starts running at \(10\) km/hr. He finds that raindrops are hitting his head vertically. The speed of raindrops with respect to the road will be:
1. \(10\) km/hr
2. \(20\) km/hr
3. \(30\) km/hr
4. \(40\) km/hr
| 1. | \(\theta = \tan^{-1}\left(\frac{1}{4}\right)\) | 2. | \(\theta = \tan^{-1}(4)\) |
| 3. | \(\theta = \tan^{-1}(2)\) | 4. | \(\theta = 45^{\circ}\) |
A particle moves in a circle of radius \(5\) cm with constant speed and time period \(0.2\pi\) s. The acceleration of the particle is:
| 1. | \(25\) m/s2 | 2. | \(36\) m/s2 |
| 3. | \(5\) m/s2 | 4. | \(15\) m/s2 |
A projectile is fired from the surface of the earth with a velocity of \(5~\text{m/s}\) and at an angle \(\theta\) with the horizontal. Another projectile fired from another planet with a velocity of \(3~\text{m/s}\) at the same angle follows a trajectory that is identical to the trajectory of the projectile fired from the Earth. The value of the acceleration due to gravity on the other planet is:
(given \(g=9.8~\text{m/s}^2\) )
| 1. | \(3.5~\text{m/s}^2\) | 2. | \(5.9~\text{m/s}^2\) |
| 3. | \(16.3~\text{m/s}^2\) | 4. | \(110.8~\text{m/s}^2\) |