Q: A car travels 120 km in 2 hours. What is its average speed in m/s? (1 km = 1000 m, 1 hour = 3600 s)

$$\frac{120 \times 1000}{2 \times 3600} = 16.7 m/s$$

Question 1

Which of the following best describes the particle model in physics?

Accepted Answer

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

Question 2

A runner jogs along a straight track. At $$t = 0 s$$, she is at $$x = 10 m. At$$ $$t = 5 s$$, she is at $$x = 40 m. $$What is her average velocity?

Accepted Answer

$$v = \frac{40\ \mathrm{m} - 10\ \mathrm{m}}{5\ \mathrm{s}} = 6\ \mathrm{m/s}$$

Question 3

Which of the following statements about displacement is correct?

Accepted Answer

Displacement is the difference between the final and initial positions, and can be negative.

Question 4

A car moves from $$x = -20 m to$$ $$x = 30 m in 10 $$seconds. What is its displacement and average velocity?

Accepted Answer

Displacement: $$50 m$$, Average velocity: $$5 m/s$$

Question 5

Which of the following is NOT a correct SI unit pairing?

Accepted Answer

Speed: hour (h)

Question 6

A scientist measures the diameter of a red blood cell as $$0.0000075 m. $$How should this be written in scientific notation with the correct number of significant figures?

Accepted Answer

$$7.5 	imes 10$$^{-6}$$ m

Question 7

A cyclist starts 3 miles east of a water tower and ends 2 miles west of the tower after half an hour. What is her displacement?

Accepted Answer

$$-5$$ miles

Question 8

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

Accepted Answer

Speed is a scalar and measures how fast an object moves; velocity is a vector and includes direction.

Question 9

A student walks 20 m east, then 30 m west. What is the total distance traveled and the displacement?

Accepted Answer

Distance: $$50 m$$, Displacement: $$-10 m$$

Question 10

Which of the following is the correct rule for significant figures when multiplying measured quantities?

Accepted Answer

The answer should have as many significant figures as the least precise measured number.

Question 11

A motion diagram shows a series of dots representing an object's position at equal time intervals. If the spacing between the dots increases, what does this indicate?

Accepted Answer

The object is speeding up.

Question 12

Which of the following is an example of a falsifiable scientific theory?

Accepted Answer

Newton's law of universal gravitation, because it makes testable predictions about the motion of planets.

Question 13

A car travels 120 km in 2 hours. What is its average speed in m/s? (1 km = 1000 m, 1 hour = 3600 s)

Accepted Answer

$$\frac{120 	imes 1000}{2 	imes 3600} = 16.7 m/s$$

Question 14

Which of the following best describes the process of converting a number less than 1 to scientific notation?

Accepted Answer

Move the decimal point to the right until it passes the first nonzero digit, and use a negative exponent.

Question 15

A motion diagram shows two runners, A and B, with equal time intervals between positions. Runner A's dots are spaced farther apart than runner B's. What can you conclude?

Accepted Answer

Runner A is moving faster than runner B.

Question 16

If a measurement is recorded as $$0.0052$$, how many significant figures does it have?

Accepted Answer

2

Question 17

A student records the following measurements: $$18.54$$, $$106.6$$, and $$12.517. $$When adding these, how many decimal places should the answer have?

Accepted Answer

The answer should have two decimal places.

Question 18

Which of the following is an example of a coordinate system used to describe position?

Accepted Answer

A straight road with a chosen origin and positive direction marked in miles.

Question 19

A car starts braking at $$x = 100 m $$and comes to rest at $$x = 40 m. $$What is the displacement during braking?

Accepted Answer

$$-60 m$$

Question 20

Which of the following is the correct way to express the radius of the Earth, $$6,370,000 m$$, in scientific notation with the correct number of significant figures?

Accepted Answer

$$6.37 	imes 10$$^{6}$$ m

Physics for Life Sciences I – Lecture 1 (Sections 1.1–1.5) Study Notes

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드