Question

question 16 (1 point)
the cosine and sine law method for calculating the sum of displacement vectors can only be used for two vectors at a time.
true
false
question 17 (1 point)
a race car completes exactly 10 laps around an oval track. which of the following pairs of quantities concerning its motion would both have values of zero?
displacement, average velocity
average speed, average acceleration
distance, average speed
average speed, average velocity
displacement, average speed

Explanation:

Question 16

The sine and cosine laws rely on triangle geometry, which only works for combining two vectors at a time (to form a triangle). To combine more than two vectors, you must iteratively combine pairs.

• Displacement is the straight-line distance from start to end; after 10 full laps, the car returns to its starting point, so displacement = 0.
• Average velocity is defined as $\frac{\text{total displacement}}{\text{total time}}$. Since displacement = 0, average velocity = 0.
• Average speed = $\frac{\text{total distance}}{\text{total time}}$; total distance is 10×track length, so speed is non-zero. Average acceleration is non-zero because direction changes constantly on an oval track.

Answer:

True

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Question 17