Question 1

Which of the following best describes the point particle model used in mechanics?

Accepted Answer

It represents an object by a single point, ignoring its size and shape.

Question 2

A ball rolls on a tabletop. Which coordinate system is most appropriate to describe its motion?

Accepted Answer

A two-dimensional coordinate system with perpendicular axes.

Question 3

Which of the following is NOT a choice you make when setting up a coordinate system for representing motion?

Accepted Answer

The mass of the object being studied.

Question 4

The average Earth-Sun distance is $1.496 	imes 10^9$ m. Which SI prefix would be most appropriate to express this distance?

Accepted Answer

Giga (G)

Question 5

The diameter of an E. coli bacterium is $1 	imes 10^{-6}$ m. How is this value expressed using SI prefixes?

Accepted Answer

$1$ \mu m$

Question 6

A runner moves along a straight track from $x = 2.0$ m to $x = 7.5$ m. What is the displacement?

Accepted Answer

$5.5$ m$

Question 7

Which of the following quantities is a vector?

Accepted Answer

Displacement

Question 8

A vector has components $A_x = 3$ and $A_y = 4$. What is its magnitude?

Accepted Answer

$5$

Question 9

If a vector points in the negative x-direction and positive y-direction, which quadrant does it lie in?

Accepted Answer

Second quadrant

Question 10

Which of the following is the correct scientific notation for 0.000 003 m?

Accepted Answer

$3 	imes 10^{-6}$ m$

Question 11

A position vs. time graph for a falling ball shows a curve that gets steeper as time increases. What does this indicate about the ball's motion?

Accepted Answer

The ball is speeding up.

Question 12

Which of the following is a correct statement about significant digits (sig figs) in physics calculations?

Accepted Answer

The answer should have the same number of significant digits as the least precise number given.

Question 13

Which of the following is a scalar quantity?

Accepted Answer

Time

Question 14

A vector $\vec{A}$ has components $A_x = -6$ and $A_y = 8$. What is its magnitude?

Accepted Answer

$10$

Question 15

If you change the orientation of your coordinate axes, what happens to the physical motion of the object?

Accepted Answer

The numbers representing the motion change, but the physical motion does not.

Question 16

Which SI prefix corresponds to $10^{-3}$?

Accepted Answer

Milli (m)

Question 17

A vector $\vec{B}$ has magnitude $|\vec{B}| = 5$ and points at an angle $	heta = 53^\circ$ from the positive x-axis. What is the y-component $B_y$?

Accepted Answer

$B_y = 5 \sin 53^\circ$

Question 18

Which of the following best describes the difference between a vector and a scalar?

Accepted Answer

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

Question 19

A car travels 100 m east, then 50 m west. What is its displacement?

Accepted Answer

$50$ m$ east

Question 20

Which of the following is the correct way to represent a vector numerically in a coordinate system?

Accepted Answer

As an ordered pair of its components, e.g., $(A_x, A_y)$.

Lecture 2: Representing Motion in Mechanics

Study Guide - Practice Questions