phy_2.9_circular motion 圓周運動 1

計算線距離 s 的公式是
The equation for calculating the linear distance s is

• $s=2\pi r$

• $s=r\theta$

•  $s=\frac{\theta}{t}$ 

•  $s=r\omega$ 

轉一圈的角距離 $\theta$ 是多少?
What is the angular distance  $\theta$  for one revolution?

• $1\pi$ rad

• $2\pi$ rad

• 360 rad

• 180 rad

物體作勻速圓周運動時，它的週期 T

When an object performs uniform circular motion, its period T

• 是它移動方向逆轉一次所需的時間。

  indicates the time taken for the moving direction of the object to reverse.

• 是它停下所需的時間。

  indicates the time taken for the object to stop.

• 是它旋轉一周所需的時間。

  indicates the time taken for the object to complete one revolution.

• 只與它的線速率有關。

  is only related to the linear speed of the object.

每秒轉 0.5 週，其週期 T = ?

0.5 revolutions per second, its period T = ?

• 0.5 s

• 5 s

• 0.2 s

• 2 s

每秒轉 0.5 週，角速率 $\omega$ =？
0.5 revolution per second, angular speed  $\omega$ = ?

• 1 rad s-1

• 2 rad s-1

•  $\pi$  rad s-1

•  $2\pi$  rad s-1

求地球自轉的角速率 $\omega$ 。 
Find the angular speed of the earth's rotation $\omega$ 。

•  $2\pi\ rad\ s^{-1}$  

•  $\frac{2\pi}{24}\ rad\ s^{-1}$  

•  $\frac{2\pi}{24\times60\times60}\ rad\ s^{-1}$  

•  $=\frac{2\pi}{60}\ rad\ s^{-1}$  

計算線速率 v 的公式是
The equation for calculating the linear speed v is

•  $v=r\theta$  

•  $v=2\pi r$  

•  $v=r\omega$  

•  $v=\frac{\theta}{t}$  

一輛單車以 0.5 rad s^-1 的角速率沿著圓形路徑行駛。已知圓形路徑的半徑為 30 m，單車的線速率 v 是多少？
A bicycle travels along a circular track of radius 30 m at a angular speed of 0.5 rad s-1. What is its linear speed v?

• 15 m s-1 

• 30 m s-1 

• 45 m s-1 

• 60 m s-1 

一輛單車以 10 m s^-1 的恆速率沿著圓形路徑行駛。已知圓形路徑的半徑為 40 m，單車的角速率 $\omega$ 是多少？
A bicycle travels along a circular track of radius 40 m at a constant speed of 10 m s-1. What is its angular speed $\omega$ ?

• 0.25 rad s-1

• 4 rad s–1

• 25 rad s–1

• 400 rad s–1

一輛單車以 10 m s^-1 的恆速率沿著圓形路徑行駛。已知圓形路徑的半徑為 40 m，單車的週期 T 是多少？
A bicycle travels along a circular track of radius 40 m at a constant speed of 10 m s-1. What is the period T of the bicycle?

•  $\frac{2\pi\times10}{40}\ s$  

•  $\frac{2\pi\times40}{10}\ s$  

•  $\frac{10}{2\pi\times40}\ s$  

•  $\frac{40}{2\pi\times10}\ s$