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Ch. 38 - Quantum Mechanics
Giancoli Douglas - Physics for Scientists and Engineers 5th edition
Giancoli Douglas5th editionPhysics for Scientists and EngineersISBN: 9780137488179당신이 사용하는 게 아니라요?교과서 변경
36장, 문제 2

Pellets of mass 2.0 g are fired in parallel paths with speeds of 150 m/s through a hole 3.0 mm in diameter. How far from the hole must you be to detect a 1.0-cm-diameter spread in the beam of pellets?

검증된 단계별 안내
1
Convert all given quantities to SI units for consistency. The mass of the pellets is 2.0 g = 0.002 kg, the speed is 150 m/s, the hole diameter is 3.0 mm = 0.003 m, and the desired spread diameter is 1.0 cm = 0.01 m.
Understand that the spread of the beam is due to the angular divergence caused by the finite size of the hole. The angular spread θ can be approximated as θ ≈ d / L, where d is the diameter of the hole and L is the distance from the hole to the point of observation.
The spread of the beam at a distance L is given by Δx = θ × L. Substituting θ ≈ d / L into this equation, we get Δx = (d / L) × L = d. To achieve a spread of 1.0 cm (0.01 m), we need to solve for L.
Rearrange the equation for L: L = Δx / θ. Since θ ≈ d / L, substitute θ = d / L into the equation to get L = Δx / (d / L). Simplify to find L = (Δx × L) / d.
Solve for L explicitly: L = Δx / d. Substitute the values Δx = 0.01 m and d = 0.003 m into the equation to calculate the distance L.

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이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
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7m
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주요 개념

질문에 올바르게 답하기 위해 반드시 이해해야 하는 핵심 개념들은 다음과 같습니다.

Projectile Motion

Projectile motion refers to the motion of an object that is launched into the air and is subject to gravitational forces. In this scenario, the pellets are fired horizontally, and their trajectory will be influenced by gravity, causing them to spread out as they travel. Understanding the principles of projectile motion helps in calculating the distance over which the pellets will spread.
추천 영상:
가이드 코스
04:44
Introduction to Projectile Motion

Kinematics

Kinematics is the branch of physics that deals with the motion of objects without considering the forces that cause the motion. It involves concepts such as velocity, acceleration, and displacement. In this problem, kinematic equations can be used to determine how far the pellets travel before they spread to a specified diameter, taking into account their initial speed and the time of flight.
추천 영상:
가이드 코스
08:25
Kinematics Equations

Beam Divergence

Beam divergence refers to the spreading of a beam of particles or waves as it travels through space. In this case, the pellets will diverge from their initial path due to their finite size and the effects of air resistance. Understanding beam divergence is crucial for calculating the distance required to achieve a specific spread in the pellet beam, as it directly relates to the initial conditions and the geometry of the setup.
추천 영상:
가이드 코스
13:40
Beam supporting an object
0