$$\Delta x = -2\,\text{mi} - 3\,\text{mi} = -5\,\text{mi}$$

$$\sqrt{(90)^2$ + (50)^2$} = 103\,\text{m}$$

$$x_f - x_i = 10\,\text{m} - (-5\,\text{m}) = 15\,\text{m}$$

$$\frac{50\,\text{m}}{10\,\text{s}} = 5\,\text{m/s}$$

$$\frac{120\,\text{m}}{6\,\text{s}} = 20\,\text{m/s}$$\, east

Question 1

Which of the following best describes the concept of 'displacement' in physics?

Accepted Answer

The change in an object's position from its initial to its final point, including direction.

Question 2

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

$$\Delta x = -2\,	ext{mi} - 3\,	ext{mi} = -5\,	ext{mi}$$

Question 3

Which statement correctly distinguishes between a scalar and a vector quantity?

Accepted Answer

A vector has magnitude and direction, while a scalar has only magnitude.

Question 4

Anna walks 90 m east and then 50 m north. What is the magnitude of her net displacement?

Accepted Answer

$$\sqrt{(90)^2$ + (50)^2$} = 103\,	ext{m}$$

Question 5

In a motion diagram, what does it indicate if the spacing between dots increases over time?

Accepted Answer

The object is speeding up.

Question 6

Which of the following is an example of a descriptive model in physics?

Accepted Answer

A diagram showing the path of a projectile.

Question 7

A car moves from position $$x_i = -5\,	ext{m} to$$ $$x_f = 10\,	ext{m}. $$What is its displacement?

Accepted Answer

$$x_f - x_i = 10\,	ext{m} - (-5\,	ext{m}) = 15\,	ext{m}$$

Question 8

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

Accepted Answer

A model that represents objects as points to simplify analysis of motion.

Question 9

A runner covers 50 m in 10 s. What is her average speed?

Accepted Answer

$$\frac{50\,	ext{m}}{10\,	ext{s}} = 5\,	ext{m/s}$$

Question 10

Which of the following is true about velocity?

Accepted Answer

Velocity describes both the speed and direction of an object's motion.

Question 11

A car travels 120 m east in 6 s. What is its average velocity?

Accepted Answer

$$\frac{120\,	ext{m}}{6\,	ext{s}} = 20\,	ext{m/s}$$\, east

Question 12

Which of the following is NOT a vector quantity?

Accepted Answer

Speed

Question 13

If a runner moves 30 m north and then 40 m east, what is the magnitude of her net displacement?

Accepted Answer

$$\sqrt{(30)^2$ + (40)^2$} = 50\,	ext{m}$$

Question 14

Which of the following best describes a coordinate system in physics?

Accepted Answer

A system with an origin and axes marked in both positive and negative directions.

Question 15

A car moves at a constant speed. What does its motion diagram look like?

Accepted Answer

Dots are spaced equally apart.

Question 16

Which of the following is an explanatory model in physics?

Accepted Answer

Newton's law of universal gravitation.

Question 17

A runner jogs along a straight track, moving from $$x = 0 m to$$ $$x = 50 m in 10 s. $$What is her average velocity?

Accepted Answer

$$\frac{50\,	ext{m}}{10\,	ext{s}} = 5\,	ext{m/s}$$

Question 18

If a vector has a magnitude of 100 m and points 29° north of east, which equation gives the angle?

Accepted Answer

$$	heta = 	an$$^{-1}$$\left(\frac{50}{90}ight)$$

Chapter 1: Representing Motion – Study Notes

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