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Ch 02: Motion Along a Straight Line
Chapter 2, Problem 2

A juggler throws a bowling pin straight up with an initial speed of 8.20 m/s. How much time elapses until the bowling pin returns to the juggler's hand?

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1
Identify the initial velocity (v_i) of the bowling pin, which is given as 8.20 m/s. The acceleration due to gravity (g) is approximately 9.81 m/s^2, acting downwards.
Use the kinematic equation for vertical motion to find the time it takes for the bowling pin to reach its highest point. The equation is v_f = v_i + at, where v_f is the final velocity (0 m/s at the highest point), a is the acceleration (-9.81 m/s^2), and t is the time.
Rearrange the equation to solve for t: t = (v_f - v_i) / a. Substitute v_f = 0 m/s, v_i = 8.20 m/s, and a = -9.81 m/s^2 to find the time to reach the highest point.
Since the motion up and down is symmetrical, the time to go up is equal to the time to come down. Therefore, double the time found in step 3 to find the total time elapsed until the bowling pin returns to the juggler's hand.
The total time calculated is the answer to how much time elapses until the bowling pin returns to the juggler's hand.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Kinematics

Kinematics is the branch of physics that describes the motion of objects without considering the forces that cause the motion. It involves concepts such as displacement, velocity, acceleration, and time. In this problem, kinematic equations can be used to analyze the motion of the bowling pin as it travels upward and then downward.
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Acceleration due to Gravity

Acceleration due to gravity is the rate at which an object accelerates towards the Earth when in free fall, typically denoted as 'g' and approximately equal to 9.81 m/s². This constant affects the bowling pin's upward and downward motion, causing it to decelerate as it rises and accelerate as it falls back down. Understanding this concept is crucial for calculating the total time of flight.
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Time of Flight

Time of flight refers to the total time an object spends in the air during its motion. For a projectile thrown vertically, the time of flight can be determined by analyzing the time taken to reach the maximum height and the time taken to return to the starting point. In this case, the time can be calculated using kinematic equations that incorporate initial velocity and acceleration due to gravity.
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