Free physics question bank
River problem questions with solutions
Practice Kinematics part-3 Relative motion for JEE Main, JEE Advanced, NEET, and Classes 11–12. Attempt each question, then open it for the full solution.
Showing 1–10 of 43 questions
- MCQmediumKinematics part-3 Relative motion
A man crosses a river flowing at 5 m s⁻¹ and reaches a point directly opposite, 60 m away, in 5 s. His speed in still water is:
Options
JEE MainsNEET
Open question & full solution → - MCQmediumKinematics part-3 Relative motion
The downstream drifts of a swimmer crossing a river at equal angular deviations towards downstream and upstream are in the ratio 2:1. The ratio of swimmer speed to current speed cannot be less than:
Options
JEE MainsNEET
Open question & full solution → - MCQeasyKinematics part-3 Relative motion
A boat is sent across a river with velocity 8 km h⁻¹ relative to water. If its resultant velocity relative to ground is 10 km h⁻¹, the river speed is:
Options
JEE MainsNEET
Open question & full solution → - ParagraphdifficultKinematics part-3 Relative motion
When a boat moves in water, its ground velocity is the vector sum of its velocity relative to water and the water velocity relative to ground. The water in a river moves with velocity u along +x and the river width is d. A boat starts from point (1,0), aims perpendicular to the river, and has transverse acceleration a=5t, where t is in SI units.
Sub-question 1
Obtain the total time taken to cross the river.
Options
Sub-question 2
Find the equation of trajectory of the boat.
Options
Sub-question 3
Find the drift of the boat when it is in the middle of the river.
Options
JEE MainsJEE Advanced
Open question & full solution → - MCQeasyKinematics part-3 Relative motionOpen question & full solution →
A swimmer can swim at 5 m/s relative to water. A river flows at 3 m/s and is 80 m wide. The swimmer chooses his direction so that he reaches the point directly opposite. The crossing time is:
Options
- MCQmediumKinematics part-3 Relative motionOpen question & full solution →
A river of width 100 m flows east at 3 m/s. A boat can move at 5 m/s relative to water. A target on the opposite bank starts directly opposite the boat and moves east at 1 m/s. To hit the moving target, the westward component of the boat's velocity relative to water must be:
Options
- MCQeasyKinematics part-3 Relative motionOpen question & full solution →
A river of width 120 m flows east at 3 m/s. A boat can move at 5 m/s relative to water. To cross the river in minimum possible time, the boat should be pointed:
Options
- MatchdifficultKinematics part-3 Relative motion
Match Column-I with Column-II.
List 1
A. Swimmer 5 m s⁻¹, river 4 m s⁻¹: angle between swimming direction and river flow for minimum drift
B. Swimmer 5 m s⁻¹, river 3 m s⁻¹: angle between swimmer velocity relative to river and river flow for minimum crossing time
C. Swimmer 4 m s⁻¹, river 3 m s⁻¹: angle of resultant ground velocity with river flow when swimmer aims perpendicular to flow
D. Wind southwest at 3√2 m s⁻¹; man west at 7 m s⁻¹: angle between flag direction and north
List 2
p. 53°
q. 127°
r. 143°
s. 90°
Options
JEE MainsJEE Advanced
Open question & full solution → - MCQmediumKinematics part-3 Relative motionOpen question & full solution →
A river of width d flows with speed v. A swimmer has speed u relative to water and wants to reach a point B on the opposite bank located L downstream from the point directly opposite his start A. Let S = √(d² + L²). Assuming the target is reachable, the minimum time to reach B is:
Options
- MCQeasyKinematics part-3 Relative motionOpen question & full solution →
A river of width 120 m flows east at 3 m/s. A boat moves at 5 m/s relative to water. To reach the point directly opposite, it is pointed at angle θ upstream from the perpendicular to the bank. Then:
Options