/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 1 A good baseball pitcher can thro... [FREE SOLUTION] | 91Ó°ÊÓ

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A good baseball pitcher can throw a baseball toward home plate at \(85 \mathrm{mi} / \mathrm{h}\) with a spin of 1800 rev/min. How many revolutions does the baseball make on its way to home plate? For simplicity, assume that the \(60 \mathrm{ft}\) path is a straight line.

Short Answer

Expert verified
The baseball makes 14 revolutions.

Step by step solution

01

Convert speed to feet per minute

First, convert the speed of the baseball from miles per hour to feet per minute. Since 1 mile is 5280 feet and 1 hour is 60 minutes, \(85 \text{ mi/h}\) is converted by multiplying by \(\frac{5280 \text{ ft}}{\text{mi}}\) and \(\frac{1 \text{ h}}{60 \text{ min}}\). \[85 \times \frac{5280}{60} = 7480 \text{ ft/min}\]
02

Find the time to reach home plate

To find out how long it takes for the baseball to reach home plate, use the formula for time, which is distance divided by speed. The distance is 60 feet and the speed is 7480 feet per minute from the previous step:\[\text{Time} = \frac{60 \text{ ft}}{7480 \text{ ft/min}} = \frac{1}{124.67} \text{ min}\]
03

Determine revolutions per minute

The baseball spins at 1800 revolutions per minute (rev/min). Calculate how many revolutions occur in the time it takes to travel 60 feet. Use the previously calculated time:\[\text{Revolutions} = 1800 \times \frac{1}{124.67} \approx 14.47 \text{ revolutions}\]
04

Round to nearest whole number

Since the baseball can't make a fraction of a revolution, round the number of revolutions to the nearest whole number:\(14.47\) rounds to \(14\) revolutions.

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Key Concepts

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

Kinematics
Kinematics is a branch of mechanics that deals with motion, without considering the forces that lead to the motion. This includes describing the position, velocity, and acceleration of an object over time. In this baseball problem, kinematics is applied to determine how the baseball travels towards home plate. We use the formula for velocity, which is the change in distance over time (\(v = \frac{d}{t}\)), to analyze how fast the baseball moves from the pitcher's hand to home plate.

Understanding kinematics is crucial for solving problems involving linear motion, as it allows for precise calculations of how fast and how far an object travels. In our problem, we determine the time it takes for the baseball to travel 60 feet, offering insight into its flight characteristics based on its velocity.
Rotational Motion
Rotational motion involves objects that spin around a central axis. In our baseball example, we're not only concerned with the linear path of the ball but also with how it spins. The baseball makes a specific number of revolutions as it travels, which is essential in sports for understanding control and movement in the air.

To consider rotational motion, the formula for angular velocity or revolutions per minute (\(\omega = 2\pi \times \text{RPM}\)) becomes relevant. While the spin might not directly affect the straight-line distance calculation, it influences how we perceive the ball’s behavior, such as its trajectory curve due to the Magnus effect, where spinning influences the path by altering air pressure on different sides of the ball.
Unit Conversion
Unit conversion is a fundamental part of problem-solving in physics. Converting units allows for standardized calculations and comparisons. In this problem, we begin with the speed provided in miles per hour and convert it to feet per minute for easier calculations. This involves multiplying by conversion factors such as 5280 feet per mile and 1 hour per 60 minutes.

To solve the homework problem, understanding unit conversion ensures the equations align correctly, offering precise and comparable results. Unit conversion is crucial in transforming given quantities into compatible units for calculations, helping maintain consistency across various systems of measurement.
Mathematical Calculation
Mathematical calculations in physics allow us to derive accurate, empirical results from theoretical concepts. This exercise involves several crucial calculations:
  • Calculating feet per minute from miles per hour.
  • Determining time using the formula \(\text{Time} = \frac{\text{Distance}}{\text{Speed}}\).
  • Using revolutions per minute (RPM) to find the number of revolutions during the baseball's travel.
Each of these calculations uses simple math principles, such as multiplication and division, which are key to deriving meaningful results from physical principles. By breaking down each step with conversion factors and formulas, the problem is resolved in an understandable and systematic way.

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Most popular questions from this chapter

At 7: 14 A.M. on June 30,1908 , a huge explosion occurred above remote central Siberia, at latitude \(61^{\circ} \mathrm{N}\) and longitude \(102^{\circ}\) \(\mathrm{E} ;\) the fireball thus created was the brightest flash seen by anyone before nuclear weapons. The Tunguska Event, which according to one chance witness "covered an enormous part of the sky," was probably the explosion of a stony asteroid about \(140 \mathrm{~m}\) wide. (a) Considering only Earth's rotation, determine how much later the asteroid would have had to arrive to put the explosion above Helsinki at longitude \(25^{\circ} \mathrm{E}\). This would have obliterated the city. (b) If the asteroid had, instead, been a metallic asteroid, it could have reached Earth's surface. How much later would such an asteroid have had to arrive to put the impact in the Atlantic Ocean at longitude \(20^{\circ} \mathrm{W} ?\) (The resulting tsunamis would have wiped out coastal civilization on both sides of the Atlantic.)

A merry-go-round rotates from rest with an angular acceleration of \(1.50 \mathrm{rad} / \mathrm{s}^{2}\). How long does it take to rotate through (a) the first \(2.00\) rev and (b) the next \(2.00\) rev?

A meter stick is held vertically with one end on the floor and is then allowed to fall. Find the speed of the other end just before it hits the floor, assuming that the end on the floor does not slip. (Hint: Consider the stick to be a thin rod and use the conservation of energy principle.)

A thin rod of length \(0.75 \mathrm{~m}\) and mass \(0.42 \mathrm{~kg}\) is suspended freely from one end. It is pulled to one side and then allowed to swing like a pendulum, passing through its lowest position with angular speed \(4.0 \mathrm{rad} / \mathrm{s}\). Neglecting friction and air resistance, find (a) the rod's kinetic energy at its lowest position and (b) how far above that position the center of mass rises.

A drum rotates around its central axis at an angular velocity of \(12.60 \mathrm{rad} / \mathrm{s}\). If the drum then slows at a constant rate of \(4.20 \mathrm{rad} / \mathrm{s}^{2}\) (a) how much time does it take and (b) through what angle does it rotate in coming to rest?

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