Question

A boat is rowing in a river at the rate of 4.8 km/hr with respect to river. The river flows at the rate of 6 km/hr. The speed of boat in m/s can be :
(1) 3.1
(2) 2.1
(3) 4.5
(4) 5​

Answer 1

Explanation:

to convert km/h into m/s we multiply by 5/18

Answer 2

A boat is rowing in a river at the rate of 4.8 km/ hr with respect to river. The river flows at the rate of 6 km/hr. The speed of boat is 2.13 m/s

Explanation:

Given:

• A boat is rowing in a river at the rate of 4.8 km/ hr
• The river flows at the rate of 6 km/hr

To find: The speed of the boat

The boat velocity and the river velocity will give the boat new resultant velocity.

The boat velocity is perpendicular to river velocity.

Assume that,

$V_{B} = Velocity of boat = 4.8 km /hr$

$V_{R} = Velocity of river = 6 km/hr$

Apply Pythagoras theorem,

$Resultant velocity boat^{2} = V_{B} ^{2}+V_{R} ^{2}$

$Resultant Velocity boat = \sqrt{(4.8)^{2}+6^{2} }$

Resultant velocity boat = $\sqrt{23.04+36}$

Velocity = $\sqrt{59.04}$

Velocity = 7.68

⇒ 7.68 (5/18) km/hr

= 2.13 m/s

Final answer:

A boat is rowing in a river at the rate of 4.8 km/ hr with respect to river. The river flows at the rate of 6 km/hr. The speed of boat is 2.13 m/s

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