Rain is falling vertically downward with a speed of \(35~\text{m/s}.\) The wind starts blowing after some time with a speed of \(12~\text{m/s}\) in the east to the west direction. The direction in which a boy standing at the place should hold his umbrella is:
1. | \(\text{tan}^{-1}\Big(\frac{12}{37}\Big)\) with respect to rain |
2. | \(\text{tan}^{-1}\Big(\frac{12}{37}\Big)\) with respect to wind |
3. | \(\text{tan}^{-1}\Big(\frac{12}{35}\Big)\) with respect to rain |
4. | \(\text{tan}^{-1}\Big(\frac{12}{35}\Big)\) with respect to wind |
1. | \(10\) min | 2. | \(5\sqrt3\) min |
3. | \(20\) min | 4. | \(\dfrac{10}{\sqrt3}\) min |
A motorboat is racing towards the north at \(25\) km/h and the water current in that region is \(10\) km/h in the direction of \(60^\circ\) east of the south. The resultant velocity of the boat is:
1. | \(12\) km/h at \(23 . 4^\circ\) east of west |
2. | \(22\) km/h at \(23 . 4^\circ\) north of east |
3. | \(22\) km/h at \(23 . 4^\circ\) east of north |
4. | \(20\) km/h at \(23 . 4^\circ\) north of west |
Rain is falling vertically with a speed of \(30\) m/s. A woman rides a bicycle with a speed of \(10\) m/s in the north to south direction. What is the direction in which she should hold her umbrella? [Given: \(\tan 16^{\circ}= 0.29, \& \tan 18^{\circ}= 0.33]\)
1. | \(16^{\circ}\) with the vertical, towards north |
2. | \(18^{\circ}\) with the vertical, towards north |
3. | \(16^{\circ}\) with the vertical, towards south |
4. | \(18^{\circ}\) with the vertical, towards south |
A boat is moving with a velocity \(3\hat i+ 4\hat j\) with respect to ground. The water in the river is moving with a velocity \(-3\hat i- 4\hat j\) with respect to the ground. The relative velocity of the boat with respect to water is:
1. \(8\hat j\)
2. \(-6\hat i-8\hat j\)
3. \(6\hat i + 8\hat j\)
4. \(5\sqrt{2}\)
Assertion (A): | If two particles move with uniform accelerations in different directions, then their relative velocity changes in direction. |
Reason (R): | Since the acceleration are in different directions, there is a relative acceleration and hence the relative velocity changes. |
1. | (A) is True but (R) is False. |
2. | (A) is False but (R) is True. |
3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
Two bullets are fired horizontally and simultaneously towards each other from the rooftops of two buildings (building being \(100~\text{m}\) apart and being of the same height of \(200~\text{m}\)) with the same velocity of \(25~\text{m/s}.\) When and where will the two bullets collide?
\((g = 10~\text{m/s}^2)\)
1. | After \(2~\text{s}\) at a height of \(180~\text{m}\) |
2. | After \(2~\text{s}\) at a height of \(20~\text{m}\) |
3. | After \(4~\text{s}\) at a height of \(120~\text{m}\) |
4. | They will not collide. |
Rain is falling vertically with a speed of \(35\) m/s. A woman rides a bicycle with a speed of \(12\) m/s in the east-to-west direction. What is the direction in which she should hold her umbrella?
1. | in the vertical direction only. |
2. | \(19^\circ\) with vertical towards east. |
3. | \(19^\circ\) with vertical towards the west. |
4. | \(19^\circ\) with vertical towards the south. |