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An airplane propeller is rotating at 1900 rpm (rev/min). (a) Compute the propeller's angular velocity in rad/s. (b) How many seconds does it take for the propeller to turn through \(35^{\circ} ?\)

Short Answer

Expert verified
The angular velocity of the airplane propeller in rad/s can be found by applying the values in the formula mentioned in Step 2. After that, to find out how many seconds it takes for the propeller to turn through \(35^{\circ}\), convert the angle from degrees to radians (as mentioned in Step 3) and use this value and the previously calculated angular velocity in the formula for time (as laid out in Step 5).

Step by step solution

01

Conversion from rpm to rad/s

To convert the speed from revolutions per minute (rpm) to rad/s, we use the fact that one revolution corresponds to \(2\pi\) radians and one minute has 60 seconds. Hence, the propeller's angular speed \(\omega\) in rad/s is given by \(\omega = 1900 \times \(\frac{2\pi}{60}\).
02

Calculation of angular speed in rad/s

To calculate \(\omega\), simply substitute the given values and apply the operation. Ensure to use the constant \(\pi\).
03

Conversion from degrees to radians

To compute the time it takes for the propeller to spin through \(35^{\circ}\), we first need to convert this angle from degrees to radians because our angular velocity is in rad/s. We use the conversion factor \( \frac{\pi}{180}\) for this step; hence, our angle in radians will be \(35 \times \(\frac{\pi}{180}\)\).
04

Calculation of time for the propeller to turn through \(35^{\circ}\)

Time \(t\) for the propeller to turn through \(35^{\circ}\) is given as \(t = \frac{\theta}{\omega}\), where theta \(\theta\) is \(35^{\circ}\) in radians and \(\omega\) is the angular speed computed in Step 2.
05

Calculation of the time duration

Plug in the values of \(\theta\) and \(\omega\) obtained from the previous steps into the expression for \(t\) to calculate the time duration.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Propeller Motion
Propeller motion involves the rotation of the propeller blades around an axis, typically powered by the engine of an airplane. This motion is critical for generating thrust, enabling the aircraft to move forward. To describe propeller motion mathematically, we often refer to angular velocity, which represents how quickly the propeller turns. The movement of a propeller can be complex, with factors such as air resistance and engine power affecting the motion. However, understanding the basics through angular velocity helps us anticipate propeller behavior. To comprehend the speed at which a propeller rotates, we need to convert the rotational speed into more universally understood terms like radians per second.
RPM to Rad/S Conversion
When working with the rotational speed of objects like airplane propellers, often specified in revolutions per minute (rpm), it's crucial to convert this into angular velocity measured in radians per second (rad/s) for more versatile use in calculations. To convert rpm to rad/s:
  • Recognize that one revolution is equivalent to an angle of \(2\pi\) radians.
  • Remember that one minute comprises 60 seconds.
  • Use the conversion formula: \(\omega = \text{rpm} \times \frac{2\pi}{60}\).
For instance, a propeller speed of 1900 rpm converts to rad/s by substituting the value into the formula: \(1900 \times \frac{2\pi}{60}\). This calculation is integral in addressing problems involving angular velocity, allowing for seamless transitions into other units and ensuring accuracy in various engineering and physics applications.
Rotation Angle Conversion
In physics, especially when dealing with rotational motion, angles are often more effectively measured in radians than degrees. This is because radians provide a direct relationship between the linear and rotational dynamics best depicted in equations. To convert angles from degrees to radians:
  • Understand that \(\pi\) radians equal 180 degrees.
  • Use the conversion factor: \(\frac{\pi}{180}\).
For example, to convert a \(35^{\circ}\) angle to radians, apply the conversion: \(35 \times \frac{\pi}{180}\). This conversion is vital when calculating the time it takes for a propeller to complete a certain degree of rotation, especially when combined with angular velocities measured in rad/s. Understanding this principle gives precise interpretation in calculating real-world rotational scenarios, such as analyzing aircraft propulsion dynamics.

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Most popular questions from this chapter

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