Rankers Physics

Relative Motion in Two Dimension: Practice Problem & Solution

Rain drops are falling vertically and a man is running on the ground horizontally with speed equal to the rain with respect to the ground. Rain drops appears to him hitting with velocity 10 km/hr. Find velocity of rain.
5 km/hr
10 km/hr
5√2 km/hr
10√2 km/hr

Solution Explained:

To solve this problem, we apply the core principles of Relative Motion in Two Dimension. Understanding the underlying formula is key to arriving at the correct answer below:

Velocity of Rain = - V j

Velocity of Person = V i

Velocity of Rain with respect to the Person = - V i - V j

so, V√2 = 10 ⇒ V = 5√2 km/hr

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