Question 1

A fish swims upstream against a current. If the fish exerts a force $$F at an $$angle $$	heta to $$the direction of the current, which of the following best describes the net work done by the fish over a distance $$d$$?

Accepted Answer

$$W = F d \cos 	heta$$

Question 2

In the context of energy and motion, which of the following statements is correct regarding kinetic energy?

Accepted Answer

Kinetic energy is given by $$K = \frac{1}{2} m v^2$ and depends on the mass and the square of the velocity of the object.

Question 3

A fish of mass $$m$$ jumps out of water and reaches a maximum height $$h$$ above the water surface. What is the initial velocity $$v_0 of $$the fish as it leaves the water?

Accepted Answer

$$v_0$$ = \sqrt{2 g h}$$

Question 4

Which of the following best describes the relationship between work and energy in the context of a fish swimming upstream?

Accepted Answer

The work done by the fish against the current is dissipated as heat due to water resistance.

Question 5

A fish of mass $$2\ \mathrm{kg}$$ swims at a constant speed of $$1.5\ \mathrm{m/s}$$ against a current. What is its kinetic energy?

Accepted Answer

$$4.5\ \mathrm{J}$$

Question 6

If a fish exerts a force of $$5\ \mathrm{N} to $$swim upstream at a constant velocity for $$10\ \mathrm{m}$$, how much work does it do?

Accepted Answer

$$50\ \mathrm{J}$$

Question 7

Which of the following best explains why a fish must continuously exert force to swim at constant speed in water?

Accepted Answer

Because water resistance (drag) opposes the fish's motion, requiring a continuous force to maintain constant velocity.

Question 8

A fish swims in a circular path of radius $$r at $$constant speed $$v. $$What is the direction of the net force acting on the fish?

Accepted Answer

Toward the center of the circle

Question 9

If a fish of mass $$m is $$moving in a circle of radius $$r$$ with speed $$v$$, what is the magnitude of the net force acting on it?

Accepted Answer

$$F = \frac{m v^2$}{r}$$

Question 10

A fish accelerates from rest to a speed $$v in $$time $$t by $$exerting a constant force $$F. $$What is the mass of the fish?

Accepted Answer

$$m = \frac{F t}{v}$$

Question 11

Which of the following is a correct statement about energy and motion for a fish swimming at constant speed in a straight line?

Accepted Answer

The net force on the fish is zero, but it must still do work to overcome drag.

Question 12

A fish of mass $$1\ \mathrm{kg}$$ jumps vertically out of the water and reaches a height of $$2\ \mathrm{m}. $$What is the change in gravitational potential energy?

Accepted Answer

$$19.6\ \mathrm{J}$$

Question 13

If a fish swims in a spiral path, which of the following best describes the type of motion?

Accepted Answer

The fish is undergoing both rotational and translational motion.

Question 14

A fish exerts a force at an angle to its direction of motion. Which component of the force contributes to the fish's forward motion?

Accepted Answer

The component parallel to the direction of motion, $$F \cos 	heta$$

Question 15

A fish of mass $$0.5\ \mathrm{kg}$$ accelerates from $$0 to$$ $$2\ \mathrm{m/s} in$$ $$4\ \mathrm{s}. $$What is the average force exerted by the fish?

Accepted Answer

$$0.25\ \mathrm{N}$$

Question 16

Which of the following best describes the energy transformation when a fish jumps out of water and falls back in?

Accepted Answer

Chemical energy is converted to kinetic energy, then to potential energy, and back to kinetic energy.

Fluid Mechanics and Energy in Physics

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