Q: A car travels 120 km in 2 hours. What is its average speed, and how does this differ from its average velocity if the car returns to its starting point?

Average speed is $$60\ \text{km/h}$$; average velocity is $$0\ \text{km/h}$$ because displacement is zero.

Q: A projectile is launched from ground level with an initial velocity of $$v_0 at an $$angle $$\theta$$ above the horizontal. Which equation gives the time of flight until it returns to the ground (neglecting air resistance)?

$$t = \dfrac{2 v_0$ \sin \theta}{g}$$

Q: Which of the following statements about free fall on planet Earth is correct?

The acceleration is constant and equal to $$-9.8\ \text{m/s}^2$$ downward.

Q: A vector $$\vec{A}$$ has a magnitude of $$5$$ units and points $$53^\circ$$ above the positive x-axis. What are its x and y components?

$$A_x = 3\ \text{units},\ A_y = 4\ \text{units}$$

Q: A ball is thrown vertically upward with an initial velocity of $$10\ \text{m/s}. $$How long does it take to reach its maximum height?

$$t = \dfrac{v_0$}{g} = \dfrac{10}{9.8} \approx 1.02\ \text{s}$$

Q: A car accelerates from rest at $$2\ \text{m/s}^2$$ for $$5\ \text{s}. $$What is its final velocity?

$$v = v_0$ + a t = 0 + 2 \times 5 = 10\ \text{m/s}$$

Question 1

A car travels 120 km in 2 hours. What is its average speed, and how does this differ from its average velocity if the car returns to its starting point?

Accepted Answer

Average speed is $$60\ 	ext{km/h}$$; average velocity is $$0\ 	ext{km/h}$$ because displacement is zero.

Question 2

Which of the following best describes the difference between displacement and distance traveled?

Accepted Answer

Displacement is the straight-line change in position, while distance is the total path length traveled.

Question 3

A projectile is launched from ground level with an initial velocity of $$v_0 at an $$angle $$	heta$$ above the horizontal. Which equation gives the time of flight until it returns to the ground (neglecting air resistance)?

Accepted Answer

$$t = \dfrac{2 v_0$ \sin 	heta}{g}$$

Question 4

Which of the following statements about free fall on planet Earth is correct?

Accepted Answer

The acceleration is constant and equal to $$-9.8\ 	ext{m/s}^2$$ downward.

Question 5

A vector $$\vec{A}$$ has a magnitude of $$5$$ units and points $$53^\circ$$ above the positive x-axis. What are its x and y components?

Accepted Answer

$$A_x = 3\ 	ext{units},\ A_y = 4\ 	ext{units}$$

Question 6

Which of the following is NOT a correct application of dimensional analysis?

Accepted Answer

Adding quantities with different units, such as meters and seconds.

Question 7

A ball is thrown vertically upward with an initial velocity of $$10\ 	ext{m/s}. $$How long does it take to reach its maximum height?

Accepted Answer

$$t = \dfrac{v_0$}{g} = \dfrac{10}{9.8} \approx 1.02\ 	ext{s}$$

Question 8

Which of the following best describes centripetal acceleration in uniform circular motion?

Accepted Answer

It is directed toward the center of the circle and has magnitude $$a_c = \dfrac{v^2$}{r}.$$

Question 9

A cyclist travels east for $$3\ 	ext{km}$$, then north for $$4\ 	ext{km}. $$What is the magnitude of the displacement from the starting point?

Accepted Answer

$$5\ 	ext{km}$$

Question 10

Which of the following is the correct kinematic equation for displacement with constant acceleration?

Accepted Answer

$$x = x_0$ + v_0$ t + \dfrac{1}{2} a t^2$

Question 11

A student measures the length of a table as $$2.50\ 	ext{m}$$, $$2.5\ 	ext{m}$$, and $$2.500\ 	ext{m}. $$Which measurement has the greatest number of significant figures?

Accepted Answer

$$2.500\ 	ext{m}$$

Question 12

A car accelerates from rest at $$2\ 	ext{m/s}^2$$ for $$5\ 	ext{s}. $$What is its final velocity?

Accepted Answer

$$v = v_0$ + a t = 0 + 2 	imes 5 = 10\ 	ext{m/s}$$

Question 13

Which of the following is always true for projectile motion on planet Earth (neglecting air resistance)?

Accepted Answer

The horizontal acceleration is zero, and the vertical acceleration is $$-9.8\ 	ext{m/s}^2.$$

Question 14

A particle moves in a circle of radius $$r$$ with constant speed $$v. $$What is the period $$T of $$the motion?

Accepted Answer

$$T = \dfrac{2 \pi r}{v}$$

Question 15

Which of the following best describes the angular speed $$\omega in $$uniform circular motion?

Accepted Answer

$$\omega = \dfrac{2 \pi}{T}$$

Question 16

A vector $$\vec{B} is $$given in unit vector form as $$\vec{B} = 2 \hat{i} + 3 \hat{j}. $$What is its magnitude?

Accepted Answer

$$\sqrt{2^2$ + 3^2$} = \sqrt{13} \approx 3.61$$

Question 17

A car moves along the x-axis. At $$t = 0$$, it is at $$x_0 = 0$. It accelerates at a = 2$$\ 	ext{m/s}^2$$ for t = 4$$\ 	ext{s}$$ from rest. What is its displacement?

Accepted Answer

$$x = x_0$ + v_0$ t + \dfrac{1}{2} a t^2$ = 0 + 0 + \dfrac{1}{2} 	imes 2 	imes 16 = 16\ 	ext{m}$$

Question 18

Which of the following statements about radial and tangential acceleration is correct?

Accepted Answer

Radial acceleration points toward the center of the circle, while tangential acceleration is perpendicular to radial acceleration.

PHYS 180 Study Guide: Chapters 1–4 (Units, Kinematics, Vectors, and Circular Motion)

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드