Explore topic-wise InterviewSolutions in .

This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.

1.

A train of `150 m` length is going toward north direction at a speed of `10 ms^-1`. A parrot flies at a speed of `5 ms^-1` toward south direction parallel to the railway track. The time taken by the parrot to cross the train is equal to.A. `30s`B. `15s`C. `8s`D. `10s`

Answer» Correct Answer - D
`t=50/(10+5)=10s`
Discussion
2.

A boat crosses a river with a velocity of `8(km)/(h)`. If the resulting velocity of boat is `10(km)/(h)` then the velocity of river water isA. `12.8 km//h`B. `6 km//h`C. `8km//h`D. `10 km//h`

Answer» Correct Answer - B
`vec(v)_(r//g)=vec(v)hati,vec(v)_(b//r)=8 hatj, |vec(v)_(b//g)|=10`
`vec(v)_(b//g)=vec(v)_(b//r)+vec(v)_(r//g)=8hatj+vhati`
`|vec(v)_(b//g)|=sqrt((8)^(2)+v^(2))`
`10=64+v^(2) implies v=6km//h`
Discussion
3.

A boat is moving with a velocity `3 hat i+ 4hat j` with respect to ground. The water in the river is moving with a velocity `-3 hat i - 4 hat j` with respect to ground. The relative velocity of the boat with respect to water is.A. `8j`B. `-6i-8j`C. `6i+8j`D. `5sqrt(2)`

Answer» Correct Answer - C
`vec(v)_(b//g)=3i+4j`
`vec(v)_(w//g)=-3i-4j`
`vec(v)_(b//w)=vec(v)_(b//g)-vec(v)_(b//g)-vec(v)_(w//g)=6i+8j`
Discussion
4.

In the previous problem, How far from the point directly opposite to the starting point does the man reach the opposite bankA. `1//6sqrt(3)km`B. `2//3sqrt(3)km`C. `4//3sqrt(3) km`D. `5//sqrt(3) km`

Answer» Correct Answer - A
`x=(2-3sin30^(@))t=1/(2) . 1/(3sqrt(3))`
`=1/(6sqrt(3)) km`
Discussion
5.

A motorboat coverse a distance between two points in `4h` along the flow and in `8h` opposite to the flow. In how much time, distance can be covered in still water?

Answer» Let `d`: distance between two points
`v`: velocity of motorboat in still water
`u`: velocity of river flow
Along the flow : `v_(b//g)=v+u`
`d/(v+u)=4.........(i)`
`implies v+u=d/4.......(ii)`
Opposite to the flow : `v_(b//g)=v-u`
`d/(v-u)=8.........(iii)`
`implies v-u=d/8.......(iv)`
Time taken by boat to cover distance `d` in still water `t_(0)=d/v`.
Adding (ii) and (iv), we get
`2v=d/4+d/8=(3d)/8`
`d/v=16/3 h`
The motorboat will cover the distance in `16/3 h`.
Discussion