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Estimation of physical activity levels using cell phone questionnaires: a comparison with accelerometry for evaluation of between-subject and within-subject variations.

A) True
B) False

1 Answer

2 votes

Final answer:

The position vs time graph of an accelerating object is a curve, not a straight line; it is false. The plot of displacement versus time for constant acceleration is a curved line, but against time squared, it's a straight line; it is true. A pebble dropped in water is an example of a pulse wave; it is true.

Step-by-step explanation:

The statement 'True or False: The position vs time graph of an object that is speeding up is a straight line' is false. When an object is speeding up, the graph of position versus time is a curve that gets steeper over time. A straight line would indicate a constant speed, not acceleration.

The statement 'True or False: Consider an object moving with constant acceleration. The plot of displacement versus time for such motion is a curved line while the plot of displacement versus time squared is a straight line' is true. A plot of displacement vs. time for an object under constant acceleration is indeed a curve (a parabola), and if we plot the displacement against time squared, it will form a straight line - this is because the relationship is quadratic.

The statement 'Is the following statement true or false? A pebble dropped in water is an example of a pulse wave' is true. A pulse wave is a single disturbance that moves through a medium, and a pebble creating a ripple in water is a classic example of such a disturbance.

User Bojan Kseneman
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