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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 16 questions
- MCQdifficultKinematics part-3 Relative motionOpen question & full solution →
A river of width d has speed varying across the width as v(y) = v₀[1 - ((2y - d)/d)²], where y = 0 and y = d are the banks. A swimmer moves perpendicular to the banks with constant speed u relative to water. The downstream drift is:
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- 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:
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- MCQmediumKinematics part-3 Relative motionOpen question & full solution →
A river of width d flows downstream with speed v. A swimmer of speed u relative to water starts from A and wants to reach B on the opposite bank, where B is a distance L downstream from the point directly opposite A. If θ is measured downstream from the perpendicular to the bank, the condition for a straight ground path from A to B is:
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- MCQeasyKinematics part-3 Relative motionOpen question & full solution →
A river is 200 m wide and flows at 4 m/s. A boat moves at 5 m/s relative to water and is directed perpendicular to the bank. Its downstream drift while crossing is:
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- 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:
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- MCQeasyKinematics part-3 Relative motionOpen question & full solution →
A river flows with speed v and a swimmer can swim with speed u relative to water, where v > u. He must cross the river and wants to minimize his downstream drift. If θ is the angle at which he swims upstream measured from the perpendicular to the bank, then:
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- MCQdifficultKinematics part-3 Relative motionOpen question & full solution →
The speed of a river varies across its width d according to v(y) = v₀y/d, where y is measured from one bank. A swimmer moves perpendicular to the banks with constant speed u relative to water. The downstream drift during crossing is:
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- MCQmediumKinematics part-3 Relative motionOpen question & full solution →
For the situation v > u in which a swimmer chooses the direction giving minimum downstream drift while crossing a river of width d, the minimum drift is:
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- 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:
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- MCQeasyKinematics part-3 Relative motionOpen question & full solution →
A river of width d flows with speed v. A swimmer can swim with speed u relative to water, where u > v. He wants to reach the point directly opposite on the other bank. The time required is:
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