Q: A typical protein consists of $$300$$ amino acids, each with an average mass of $$100$$ amu ($$1\ \text{amu} = 1.7 \times 10$$^{-27}$$\ \text{kg}). $$What is the mass of a typical protein in kg?

$$5.1 \times 10$$^{-23}$$\ \text{kg}$$

Q: Which of the following is an order-of-magnitude estimate?

Estimating a rock's speed as $$20\ \text{mph}$$ when it hits the ground, knowing it could be $$10 or$$ $$30\ \text{mph}$$ but not $$21\ \text{mph}.$$

Q: A student walks to school, slows down at $$t = 3\ \text{min}$$, then picks up the pace. Which feature of her position vs. time graph indicates she slowed down?

The slope of the graph decreases at $$t = 3\ \text{min}.$$

Question 1

Which of the following best describes the particle model of motion?

Accepted Answer

It treats a moving object as if all its mass were concentrated at a single point.

Question 2

A conservation scientist tracks an elephant using GPS collars that record positions every 10 minutes. If the elephant moves from $$(x_1$ = 200\ 	ext{m}) to$$ $$(x_2$ = 800\ 	ext{m}) in 30 $$minutes, what is the elephant's displacement?

Accepted Answer

$$600\ 	ext{m}$$

Question 3

Which of the following quantities is a vector?

Accepted Answer

Displacement

Question 4

An object moves along a straight line. Its velocity changes from $$v_1 = 5$$\ 	ext{m/s}$$ to v_2$ = 2\ 	ext{m/s} in$$ $$4\ 	ext{s}. $$What is its average acceleration?

Accepted Answer

$$-0.75\ 	ext{m/s}^2$$

Question 5

A car accelerates from rest up a $$10^	ext{o}$$ hill. Which of the following best describes the direction of its velocity and acceleration vectors?

Accepted Answer

Both velocity and acceleration vectors point up the hill.

Question 6

A ball is tossed straight up in the air. At its very highest point, what is the direction of its acceleration vector?

Accepted Answer

Points down

Question 7

For motion along a straight line, an object is speeding up if and only if:

Accepted Answer

The velocity and acceleration vectors point in the same direction.

Question 8

A rocket sled accelerates horizontally at $$a = 50\ 	ext{m/s}^2$$ for $$5.0\ 	ext{s}$$, then coasts for $$3.0\ 	ext{s} at $$constant speed. What is the total distance traveled?

Accepted Answer

$$1250\ 	ext{m}$$

Question 9

Which of the following statements about coordinate systems is correct?

Accepted Answer

The positive end of the x-axis is to the right, and the positive end of the y-axis is up.

Question 10

A student measures the mass of glucose syrup as $$14.3\ 	ext{g} in a$$ $$10.0\ 	ext{mL}$$ graduated cylinder. What is the density in SI units ($$	ext{kg/m}^3$$)?

Accepted Answer

$$1430\ 	ext{kg/m}^3$$

Question 11

When adding or subtracting measured values, the number of decimal places in the answer should:

Accepted Answer

Match the smallest number of decimal places of any number used in the calculation.

Question 12

A typical protein consists of $$300$$ amino acids, each with an average mass of $$100$$ amu ($$1\ 	ext{amu} = 1.7 	imes 10$$^{-27}$$\ 	ext{kg}). $$What is the mass of a typical protein in kg?

Accepted Answer

$$5.1 	imes 10$$^{-23}$$\ 	ext{kg}$$

Question 13

Which of the following is an order-of-magnitude estimate?

Accepted Answer

Estimating a rock's speed as $$20\ 	ext{mph}$$ when it hits the ground, knowing it could be $$10 or$$ $$30\ 	ext{mph}$$ but not $$21\ 	ext{mph}.$$

Question 14

A student walks to school, slows down at $$t = 3\ 	ext{min}$$, then picks up the pace. Which feature of her position vs. time graph indicates she slowed down?

Accepted Answer

The slope of the graph decreases at $$t = 3\ 	ext{min}.$$

Question 15

Which of the following is true about significant figures when multiplying or dividing measured values?

Accepted Answer

The answer should have the same number of significant figures as the least precisely known number used in the calculation.

Question 16

A cheetah accelerates quickly, runs at top speed, then slows down. During which phase do the velocity and acceleration vectors point in opposite directions?

Accepted Answer

When the cheetah is slowing down.

Question 17

A soccer ball is kicked and rolls to a stop. Which best describes the change in its velocity vectors in a motion diagram?

Accepted Answer

The velocity vectors get shorter as the ball slows down.

Question 18

Which scenario best illustrates the importance of unit conversions in real-world applications?

Accepted Answer

The Mars Climate Orbiter burned up due to a mix-up between English and SI units.

Describing Motion: Fundamental Concepts in Physics with Calculus

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