Q. No.A man is walking on a horizontal road with a speed of 4 km/h. Suddenly, the rain starts vertically downwards with a speed of 7 km/h. The magnitude of the relative velocity of the rain with respect to the man is:
1. km/h
2. km/h
3. 8 km/h
4. 4 km/h
1. \(45^\circ\)
2. \(30^\circ\)
3. \(60^\circ\)
4. \(90^\circ\)
A boat is moving with a velocity 3i + 4j with respect to ground. The water in the river is moving with a velocity – 3i – 4j with respect to ground. The relative velocity of the boat with respect to water is
1. 8j
2. – 6i – 8j
3. 6i +8j
4.
Raindrops are falling with a speed v vertically downwards and a man is running on a horizontal road with speed u. The magnitude of the velocity of the raindrops with respect to the man is:
1. v - u
2. v + u
3. \(\sqrt{\text{v}^2 + \text{u}^2 \over 2}\)
4. \(\sqrt{\text{v}^2 + \text{u}^2}\)
A person, reaches a point directly opposite on the other bank of a flowing river, while swimming at a speed of 5 m/s at an angle of \(120^\circ\) with the flow. The speed of the flow must be:
1. \(2.5\) m/s
2. \(3\) m/s
3. \(4\) m/s
4. \(1.5\) m/s
A swimmer swims a distance d upstream in 4 s and swims an equal distance downstream in 2 s. The ratio of swimmer's speed in still water to the speed of river water will be
| 1. | \(\frac{6}{5} \) | 2. | \(\frac{3}{1} \) |
| 3. | \(\frac{5}{3} \) | 4. | \(\frac{4}{3}\) |
A man standing on a road holds his umbrella at 30° 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
A man can row a boat with a speed of 10 kmph in still water. The river flows at 6 kmph. If he crosses the river from one bank to the other along the shortest possible path, time taken to cross the river of width 1 km is:
1. 1/8 h
2. 1/4 h
3. 1/2 h
4. 1 h
When a man walks on a horizontal road with velocity 1 km/h, the rain appears to him coming vertically at a speed of 2 km/h. The actual speed of the rain with respect to ground is:
1. km/h
2. km/h
3. 1 km/h
4. 3 km/h
A man is crossing a river flowing with a velocity of 5 m/s. He reaches a point directly across the river at a distance of 60 m in 5 s. His velocity in still water should be:
1. 12 m/s
2. 13 m/s
3. 5 m/s
4. 10 m/s
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