Q: A student walks 500 meters in 10 minutes. What is her average speed in meters per second?

$$\text{Average speed} = \frac{500\ \mathrm{m}}{600\ \mathrm{s}} = 0.83\ \mathrm{m/s}$$

Q: A rocket launches vertically with an acceleration of $$30\ \mathrm{m/s^2$}$$ and runs out of fuel after 5 seconds. Neglecting air resistance, what is its velocity at the moment it runs out of fuel?

$$v = a t = 30\ \mathrm{m/s^2$} \times 5\ \mathrm{s} = 150\ \mathrm{m/s}$$

Question 1

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

Accepted Answer

An object that can be represented as a mass at a single point in space.

Question 2

A motion diagram of a car shows the distance between each position increasing over time. What does this indicate about the car's motion?

Accepted Answer

The car is accelerating.

Question 3

Which of the following quantities is a vector and requires both magnitude and direction for its complete description?

Accepted Answer

Velocity

Question 4

A cyclist is riding at 10 m/s and comes to a complete stop in 5 seconds. What is the average acceleration of the cyclist?

Accepted Answer

$$a_{avg} = \frac{v_f - v_i}{\Delta t} = \frac{0 - 10}{5} = -2\ \mathrm{m/s^2$}$$

Question 5

Which of the following is NOT a basic SI unit?

Accepted Answer

Gram

Question 6

A student walks 500 meters in 10 minutes. What is her average speed in meters per second?

Accepted Answer

$$	ext{Average speed} = \frac{500\ \mathrm{m}}{600\ \mathrm{s}} = 0.83\ \mathrm{m/s}$$

Question 7

When adding two vectors $$\vec{A}$$ and $$\vec{B}$$, which graphical method is correct?

Accepted Answer

Place the tail of $$\vec{B} at $$the tip of $$\vec{A}$$, then draw the resultant from the tail of $$\vec{A} to $$the tip of $$\vec{B}.$$

Question 8

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

Accepted Answer

Downward

Question 9

Which of the following statements about significant figures is correct?

Accepted Answer

When multiplying or dividing, the answer should have the same number of significant figures as the least precisely known input.

Question 10

A car accelerates from rest up a $$20^\circ$$ hill with $$a = 2.0\ \mathrm{m/s^2$}. $$What is the direction of the acceleration vector relative to the coordinate system?

Accepted Answer

Up the slope, at $$20^\circ to $$the horizontal

Question 11

A rocket launches vertically with an acceleration of $$30\ \mathrm{m/s^2$}$$ and runs out of fuel after 5 seconds. Neglecting air resistance, what is its velocity at the moment it runs out of fuel?

Accepted Answer

$$v = a t = 30\ \mathrm{m/s^2$} 	imes 5\ \mathrm{s} = 150\ \mathrm{m/s}$$

Question 12

Which of the following is the correct definition of displacement?

Accepted Answer

The change in position of an object, represented by $$\Delta \vec{r}.$$

Question 13

A motion diagram shows a particle slowing down as it moves in the positive x-direction. What are the signs of its velocity and acceleration?

Accepted Answer

Velocity is positive, acceleration is negative.

Question 14

Which of the following is a correct order-of-magnitude estimate for the mass of a human?

Accepted Answer

$$\sim 100\ \mathrm{kg}$$

Question 15

A position-versus-time graph for a car shows a straight line with a negative slope. What does this indicate about the car's motion?

Accepted Answer

The car is moving in the negative direction at constant speed.

Question 16

Which of the following is the correct formula for average velocity?

Accepted Answer

$$\vec{v}_{avg} = \frac{\Delta \vec{r}}{\Delta t}$$

Question 17

A student measures the length of a classroom as 8.20 m, the width as 5.2 m, and the height as 3.00 m. What is the correct number of significant figures in the calculated volume?

Accepted Answer

2 significant figures

Question 18

Which of the following is NOT included in a complete pictorial representation of a physics problem?

Accepted Answer

None of the above; all are included.

Question 19

A car travels 60 miles per hour. What is its speed in meters per second? (Use $$1\ \mathrm{mi} = 1.609\ \mathrm{km}$$ and $$1\ \mathrm{km} = 1000\ \mathrm{m})$$

Accepted Answer

$$60\ \mathrm{mi/hr} 	imes \frac{1.609\ \mathrm{km}}{1\ \mathrm{mi}} 	imes \frac{1000\ \mathrm{m}}{1\ \mathrm{km}} 	imes \frac{1\ \mathrm{hr}}{3600\ \mathrm{s}} \approx 26.8\ \mathrm{m/s}$$

Chapter 1: Concepts of Motion – Physics for Scientists and Engineers

Guida di studio - Domande di pratica

Study guide - Flashcard