# Relative Motion: Rain Example

## Trending Questions

**Q.**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

- 10 km/hr
- 20 km/hr
- 30 km/hr
- 40 km/hr

**Q.**A man sitting in a bus travelling in a direction from west to east with a speed of 40 km/h observes that the rain-drops are falling vertically down. To the another man standing on ground the rain will appear

- To fall at an angle going from east to west
- The information given is insufficient to decide the direction of rain.
- To fall vertically down
- To fall at an angle going from west to east

**Q.**

A man is coming down an incline of angle 30∘. When he walks with speed √3m/s he has to keep his umbrella vertical w.r.t. ground to protect himself from rain. The actual speed of rain is 5 m/s. At what angle with vertical should he keep his umbrella when he is at rest so that he does not get drenched?

**Q.**

Rain is falling vertically with a speed of 12ms−1.A cyclist is moving east to west with a speed of 12√3ms−1.In order to protect himself from rain at what angle he should hold his umbrella w.r.t vertical.

**Q.**

A, B, C, D are four trees, located at the vertices of a square. Wind blows from A to B with uniform speed. The ratio of times of flight of a bird from A to B and from B to A is 'n'. At what angle should the bird fly from the direction of wind flow, in order that it starts from A and reaches C.Let

**Q.**

Consider the situation given in the diagram two cars are moving along road 1 and road 2. Draw the direction of the motion of car B as seen from car A

**Q.**

A river flows due south with a speed of 2.0 m/s. A man steers a motorboat across the river; his velocity relative to the water is 4 m/s due east. The river is 800 m wide. How far south of his starting point will be reach the bank?

200 m

400 m

800 m

500 m

**Q.**

A flag is hoisted on the steamer boat.On the basis of the data given below find out the direction of flutter of

the flag

→vsteamer/water=10√3ms−1 towards North

→vwater=5ms−1 towards East

→vwind=5ms−1 towards East

(Assume the wind does not affect the steamer)

North

South

East

West

**Q.**

From the previous problem at what angle to the horizontal must be steered in order to reach a point on the opposite bank directly east from the starting point? (Assuming his speed w.r.t. to the river is 4 m/s)

**Q.**

A man wishes to cross a river in a boat. If he crosses the river in minimum time he takes 10 minutes with a drift of 120 m. If he crosses the river taking the shortest route, he takes 12.5 minutes, find the velocity of the boat with respect to water.

12 m/min

20 m/min

5 m/min

31 m/min