Question

Problem 39

Answer 1

Given information

Given Huck Finn walks at a speed of across his raft (that is, he walks perpendicular to the raft’s motion relative to the shore). The heavy raft is travelling down the Mississippi River at a speed of   relative to the river bank (Fig. 3–42).

To find: What is Huck’s velocity (speed and direction) relative to the riverbank?

Step-by-step explanation

Step 1.

Motion is relative. In other words, the description of motion can be different for different observers. In this case, the motion of person  is described differently with respect to the raft (R) and the river bank (B). Relative to the raft, the person is just moving straight across it. Meanwhile, relative to the bank, the person is moving on a diagonal path as a result of combining the person's motion and the flow of the river.

To identify person H's velocity,

• draw the relative velocity vectors
• perform vector operation in getting the magnitude and direction

The relative velocities in the problem are as follows:

•  - the person's velocity relative to the raft
•  - the raft's velocity relative to the bank
•  - the person's velocity relative to the bank