Question

Archerfish are tropical fish that hunt by shooting drops of water from their mouths at insects above the waterÂs surface to knock them into the water, where the fish can eat them. a 65-g fish at rest just at the surface of the water can expel a 0.30-g drop of water in a short burst of 5.0 ms. high-speed measurements show that the water has a speed of 2.5 m/s just after the archerfish expels it.

Answer 1

Answer:

.012

Explanation:

Take the mass of the fish and divide it by the mass of the water:

65/.30=216.667

Divide the given speed by the value we found above:

2.5/216.667=.0115

Answer can be rounded up to .012

Answer 2

The speed of the archerfish immediately after it expels the drop of water is about (b) 0.012 m/s

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Further explanation

Newton's second law of motion states that the resultant force applied to an object is directly proportional to the mass and acceleration of the object.

$\large {\boxed {F = ma }$

F = Force ( Newton )

m = Object's Mass ( kg )

a = Acceleration ( m )

Let us now tackle the problem !

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The Question:

What is the speed of the archerfish immediately after it expels the drop of water?

(a) 0.0025 m/s; (b) 0.012 m/s; (c) 0.75 m/s; (d) 2.5 m/s.

Given:

mass of fish = m₁ = 65 g

mass of drop of water = m₂ = 0.30 g

speed of water = v₂ = 2.5 m/s

initial speed of water = initial speed of archerfish = u₁ = u₂ = 0 m/s

Asked:

the speed of the archerfish = v₁ = ?

Solution:

We will use Conservation of Momentum Law as follows:

$m_1u_1 + m_2u_2 = m_1v_1 + m_2v_2$

$65(0) + 0.30(0) = 65v_1 + 0.30(2.5)$

$0 + 0 = 65v_1 + 0.75$

$65v_1 = -0.75$

$v_1 = -0.75 \div 65$

$\boxed{v_1 \approx -0.012 \texttt{ m/s}}$

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Conclusion :

The speed of the archerfish immediately after it expels the drop of water is about 0.012 m/s

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Learn more

• Impacts of Gravity : brainly.com/question/5330244
• Effect of Earth’s Gravity on Objects : brainly.com/question/8844454
• The Acceleration Due To Gravity : brainly.com/question/4189441
• Newton's Law of Motion: brainly.com/question/10431582
• Example of Newton's Law: brainly.com/question/498822

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Answer details

Grade: High School

Subject: Physics

Chapter: Dynamics