Problem 103
Your average velocity over a 10 -min period is \(2.2 \mathrm{~m} / \mathrm{s}\). Is it possible that you were at rest at some point during the \(10 \mathrm{~min}\) ?
Problem 104
Two dragonflies have the following equations of motion: $$ \begin{aligned} &x_{1}=2.2 \mathrm{~m}+(0.75 \mathrm{~m} / \mathrm{s}) t \\ &x_{2}=-3.1 \mathrm{~m}+(-1.1 \mathrm{~m} / \mathrm{s}) t \end{aligned} $$ (a) Which dragonfly is moving faster? (b) Which dragonfly starts out closer to \(x=0\) at \(t=0\) ?
Problem 107
Which has the greater displacement, object 1 , which moves from \(5.0 \mathrm{~m}\) to \(7.0 \mathrm{~m}\) in \(2.0 \mathrm{~s}\), or object 2 , which moves from \(15 \mathrm{~m}\) to \(16 \mathrm{~m}\) in \(25 \mathrm{~s}\) ? Explain.
Problem 108
What is the final position of an object that starts at \(7.3 \mathrm{~m}\) and moves with a velocity of \(-1.1 \mathrm{~m} / \mathrm{s}\) for \(3.5 \mathrm{~s}\) ?
Problem 109
(a) What is the velocity of an object that moves from \(73 \mathrm{~m}\) to \(62 \mathrm{~m}\) in \(12 \mathrm{~s}\) ? (b) What is its speed?
Problem 110
A horse is at \(x=4.3 \mathrm{~m}\) at \(t=0\) and moves with a constant velocity of \(6.7 \mathrm{~m} / \mathrm{s}\). (a) Plot the motion of the horse for the range of times from \(t=0\) to \(t=5.0 \mathrm{~s}\). (b) Write the corresponding equation of motion.
Problem 111
The equation of motion for a train on a straight track is \(x=11 \mathrm{~m}+(6.5 \mathrm{~m} / \mathrm{s})\) t. (a) Plot the position-time graph for the train from \(t=0\) to \(t=5.0 \mathrm{~s}\). (b) At what time is the train at \(x=32 \mathrm{~m}\) ?
Problem 112
Think \& Calculate A child rides a pony on a circular track whose radius is \(4.5 \mathrm{~m}\). (a) Find the distance traveled and the displacement after the child has gone halfway around the track. (b) Has the distance traveled increased, decreased, or stayed the same when the child has completed one circuit of the track? Explain. (c) Has the displacement increased, decreased, or stayed the same when the child has completed one circuit of the track? Explain. (d) Find the distance and displacement after a complete circuit of the track.
Problem 113
In heavy rush-hour traffic you drive in a straight line at \(12 \mathrm{~m} / \mathrm{s}\) for \(1.5 \mathrm{~min}\), then you have to stop for \(3.5 \mathrm{~min}\), and finally you drive at \(15 \mathrm{~m} / \mathrm{s}\) for another \(2.5 \mathrm{~min}\). (a) Plot a position-time graph for this motion. Your graph should extend from \(t=0\) to \(t=7.5 \mathrm{~min}\). (b) Use your graph from part (a) to calculate the average velocity between \(t=0\) and \(t=7.5 \mathrm{~min}\).
Problem 114
Object 1 starts at \(5.4 \mathrm{~m}\) and moves with a velocity of \(1.3 \mathrm{~m} / \mathrm{s}\). Object 2 starts at \(8.1 \mathrm{~m}\) and moves with a velocity of \(-2.2 \mathrm{~m} / \mathrm{s}\). The two objects are moving directly toward one another. (a) At what time do the objects collide? (b) What is the position of the objects when they collide?
