Q: A cyclist travels 100 m north, then 100 m east. What is the magnitude of the displacement?

$$\sqrt{2} \times 100\ \mathrm{m}$$

Question 1

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

Accepted Answer

It treats an object as if all its mass were concentrated at a single point in space.

Question 2

A car moves along a straight road. You record its position every second and notice that the distance between each recorded position increases with each frame. What does this indicate about the car's motion?

Accepted Answer

The car is speeding up.

Question 3

Which equation correctly defines the average velocity vector $$\vec{v}_{avg}$$ for an object undergoing a displacement $$\Delta \vec{r}$$ over a time interval $$\Delta t$$?

Accepted Answer

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

Question 4

A runner completes a 400 m lap in 50 s. What is her average speed?

Accepted Answer

$$8.0\ \mathrm{m/s}$$

Question 5

Which of the following statements about displacement is correct?

Accepted Answer

Displacement is the change in position and is a vector quantity.

Question 6

A skier moves at constant speed on a horizontal surface, then speeds up down a hill. Which of the following best describes the skier’s acceleration during these two phases?

Accepted Answer

Zero on the horizontal, nonzero and in the direction of motion on the hill.

Question 7

If an object’s velocity is constant, what can you say about its acceleration?

Accepted Answer

The acceleration is zero.

Question 8

A car accelerates from rest up a 20° hill. Which of the following best describes the direction of the velocity and acceleration vectors?

Accepted Answer

Both vectors point up the hill.

Question 9

Which of the following is the correct formula for average acceleration $$\vec{a}_{avg}$$ when velocity changes from $$\vec{v}_1 to$$ $$\vec{v}_2$$ over a time interval $$\Delta t$$?

Accepted Answer

$$\vec{a}_{avg} = (\vec{v}_2 - \vec{v}_1) / \Delta t$$

Question 10

A car is slowing down as it moves to the right. Which of the following is true about the directions of its velocity and acceleration vectors?

Accepted Answer

Velocity points to the right, acceleration points to the left.

Question 11

Which of the following is NOT a basic type of motion discussed in the study materials?

Accepted Answer

Thermal motion

Question 12

A stopwatch is used to measure the time interval for a runner to complete a race. If the runner starts at $$t_i = 2.0\ \mathrm{s}$$ and finishes at $$t_f = 12.5\ \mathrm{s}$$, what is the time interval $$\Delta t$$?

Accepted Answer

$$\Delta t = 10.5\ \mathrm{s}$$

Question 13

Which of the following best describes the process of vector addition as used in motion diagrams?

Accepted Answer

Place the tail of the second vector at the tip of the first, then draw the resultant from the tail of the first to the tip of the second.

Question 14

A cyclist travels 100 m north, then 100 m east. What is the magnitude of the displacement?

Accepted Answer

$$\sqrt{2} 	imes 100\ \mathrm{m}$$

Question 15

In a motion diagram, what does it mean if the dots representing an object’s position are equally spaced?

Accepted Answer

The object is moving with constant speed.

Question 16

A car’s velocity changes from $$10\ \mathrm{m/s} to$$ $$30\ \mathrm{m/s} in$$ $$5\ \mathrm{s}. $$What is the average acceleration?

Accepted Answer

$$4\ \mathrm{m/s^2$}$$

Question 17

Which of the following is a correct statement about the relationship between velocity and acceleration when an object is speeding up?

Accepted Answer

Velocity and acceleration vectors point in the same direction.

Question 18

A ball is thrown straight up. At the highest point of its path, what is true about its velocity and acceleration?

Accepted Answer

Velocity is zero, acceleration is downward.

Question 19

Which of the following is a real-world example of projectile motion?

Accepted Answer

A soccer ball kicked into the air.

Chapter 1: Concepts of Motion – Physics with Calculus Study Notes

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