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Ch 03: Motion in Two or Three Dimensions
Young & Freedman Calc - University Physics 14th Edition
Young & Freedman Calc14th EditionUniversity PhysicsISBN: 9780321973610당신이 사용하는 게 아니라요?교과서 변경
3장, 문제 35b

A river flows due south with a speed of 2.0 m/s. You steer a motorboat across the river; your velocity relative to the water is 4.2 m/s due east. The river is 500 m wide. How much time is required to cross the river?

검증된 단계별 안내
1
Identify the components of the boat's velocity. The boat's velocity relative to the water is 4.2 m/s due east, which is perpendicular to the river's flow.
Recognize that the width of the river is the distance the boat needs to travel across, which is 500 m.
Use the formula for time, \( t = \frac{d}{v} \), where \( d \) is the distance across the river (500 m) and \( v \) is the velocity of the boat relative to the water (4.2 m/s).
Substitute the values into the formula: \( t = \frac{500 \text{ m}}{4.2 \text{ m/s}} \).
Calculate the time required to cross the river using the formula from the previous step.

비슷한 문제에 대한 검증된 영상 답변:

이 영상 해법은 위 문제에 도움이 된다고 튜터들이 추천한 것입니다.
영상 길이:
3m
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주요 개념

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

Relative Velocity

Relative velocity is the velocity of an object as observed from a particular frame of reference. In this problem, the boat's velocity relative to the water is given as 4.2 m/s due east, while the river flows south at 2.0 m/s. Understanding how these velocities combine is crucial for determining the boat's actual path and speed across the river.
추천 영상:
가이드 코스
04:27
Intro to Relative Motion (Relative Velocity)

Vector Components

Vector components are the projections of a vector along the axes of a coordinate system. Here, the boat's velocity can be split into eastward and southward components. The eastward component is 4.2 m/s, and the southward component is due to the river's flow at 2.0 m/s. Calculating these components helps in determining the resultant velocity and the time to cross the river.
추천 영상:
가이드 코스
07:30
Vector Addition By Components

Time Calculation

Time calculation involves determining how long it takes for an object to travel a certain distance at a given speed. In this scenario, the width of the river is 500 m, and the boat's effective velocity across the river is 4.2 m/s. Using the formula time = distance/speed, we can calculate the time required to cross the river, focusing on the eastward component of the boat's velocity.
추천 영상:
가이드 코스
04:43
Calculating Displacement from Velocity-Time Graphs
관련 실천