Q: A rock falls from a tall canyon for 4.5 seconds with no air resistance. What is its speed just before it strikes the ground? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

$$v = g t = 9.8 \times 4.5 = 44.1\ \mathrm{m/s}$$

Q: A train starts from rest and accelerates at $$2\ \mathrm{m/s^2$}$$ for 10 seconds. What is its final speed?

$$v = a t = 2 \times 10 = 20\ \mathrm{m/s}$$

Q: A canoe is drifting left toward a hungry hippo with a velocity of $$7\ \mathrm{m/s}. $$The canoe rider starts paddling frantically, causing the canoe to travel to the right with a constant acceleration of $$6\ \mathrm{m/s^2$}. $$After 4 seconds, what is the velocity of the canoe?

$$v = v_0$ + a t = -7 + 6 \times 4 = 17\ \mathrm{m/s}$$

Question 1

Which of the following best describes the difference between a hypothesis and a guess in the scientific method?

Accepted Answer

A hypothesis is a testable prediction based on evidence, while a guess lacks systematic reasoning.

Question 2

A car accelerates from rest to 20 m/s in 5 seconds. What is the car's average acceleration?

Accepted Answer

$$a = \frac{20}{5} = 4\ \mathrm{m/s^2$}$$

Question 3

Which of the following is a scalar quantity?

Accepted Answer

Speed

Question 4

A rock falls from a tall canyon for 4.5 seconds with no air resistance. What is its speed just before it strikes the ground? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$v = g t = 9.8 	imes 4.5 = 44.1\ \mathrm{m/s}$$

Question 5

Which of the following best describes Newton's First Law?

Accepted Answer

An object at rest remains at rest and an object in motion remains in motion at constant velocity unless acted upon by a net external force.

Question 6

A train starts from rest and accelerates at $$2\ \mathrm{m/s^2$}$$ for 10 seconds. What is its final speed?

Accepted Answer

$$v = a t = 2 	imes 10 = 20\ \mathrm{m/s}$$

Question 7

Which of the following is NOT a branch of science?

Accepted Answer

Astrology

Question 8

A person walks 2 km east, then 2 km north, then 2 km west, and then 2 km south. What is the displacement?

Accepted Answer

0 km

Question 9

Which of the following best describes the difference between speed and velocity?

Accepted Answer

Speed is the magnitude of velocity and does not include direction, while velocity includes both magnitude and direction.

Question 10

A car travels at 30 m/s and crashes into a wall, coming to a stop in 2 seconds. What is the car's acceleration?

Accepted Answer

$$a = \frac{v_f - v_i}{t} = \frac{0 - 30}{2} = -15\ \mathrm{m/s^2$}$$

Question 11

Which of the following is an example of pseudoscience?

Accepted Answer

Astrology

Question 12

A canoe is drifting left toward a hungry hippo with a velocity of $$7\ \mathrm{m/s}. $$The canoe rider starts paddling frantically, causing the canoe to travel to the right with a constant acceleration of $$6\ \mathrm{m/s^2$}. $$After 4 seconds, what is the velocity of the canoe?

Accepted Answer

$$v = v_0$ + a t = -7 + 6 	imes 4 = 17\ \mathrm{m/s}$$

Question 13

Which of the following is the correct SI unit for force?

Accepted Answer

Newton ($$\mathrm{N})$$

Question 14

A person walks at 1 kilometer in 10 minutes. What is the speed in meters per second?

Accepted Answer

$$v = \frac{1000}{600} = 1.67\ \mathrm{m/s}$$

Question 15

Which of the following best describes inertia?

Accepted Answer

The tendency of an object to resist changes in its state of motion.

Question 16

A race car starts from rest and speeds up uniformly to the right until it reaches a maximum velocity of $$60\ \mathrm{m/s} in$$ $$15$$ seconds. What is the acceleration of the race car?

Accepted Answer

$$a = \frac{v_f - v_i}{t} = \frac{60 - 0}{15} = 4\ \mathrm{m/s^2$}$$

Question 17

Which of the following is the correct conversion factor from kilometers to meters?

Accepted Answer

$$1\ \mathrm{km} = 1000\ \mathrm{m}$$

Question 18

Suppose you throw a ball straight up into the air with an initial speed of $$50\ \mathrm{m/s}. $$How high will it rise? (Assume $$g = 9.8\ \mathrm{m/s^2$})$$

Accepted Answer

$$h = \frac{v^2$}{2g} = \frac{50^2$}{2 	imes 9.8} = 127.6\ \mathrm{m}$$

Question 19

Which of the following statements about acceleration is correct?

Accepted Answer

Acceleration is the rate of change of velocity with respect to time.

Fundamental Concepts and Problems in Introductory Physics

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