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Why do we use a spaceship in outer space, far from other objects, to illustrate Newton's first law? Why not a car or a train? (More than one of the following statements may be correct.) (1) A car or train touches other objects, and interacts with them. (2) A car or train can't travel fast enough. (3) The spaceship has negligible interactions with other objects. (4) A car or train interacts gravitationally with the Earth. (5) A spaceship can never experience a gravitational force.

Question: Which of the following observers might observe something that appears to violate Newton's first law of motion? Explain why. (1) A person standing still on a street corner (2) A person riding on a roller coaster (3) A passenger on a starship traveling at 0.75c toward the nearby star Alpha Centauri (4) An airplane pilot doing aerobatic loops (5) A hockey player coasting across the ice.

At 6 safter 3:00, a butterfly is observed leaving a flower whose location is$<6,-3,10>\mathbf{m}$relative to an origin on top of a nearby tree. The butterfly flies until 10 safter 3:00, when it alights on a different flower whose location is$<6.8,-4.2,11.2>\mathbf{m}$ relative to the same origin. What was the location of the butterfly at a time 8.5 safter 3:00? What assumption did you have to make in calculating this location?

Question: Which of the following statements about the velocity and momentum of an object are correct? (1) The momentum of an object is always in the same direction as its velocity (2) The momentum of an object can be either in the same direction as its velocity or in the opposite direction. (3) The momentum of an object is perpendicular to its velocity. (4) The direction of an object's momentum is not related to the direction of its velocity. (5) The direction of an object's momentum is tangent to its path.

Question: Moving objects left the traces labeled A-F in Figure 1.54. The dots were deposited at equal time intervals (for example, one dot each second). In each case the object starts from the square. Which trajectories show evidence that the moving object was interacting with another object somewhere? If there is evidence of an interaction, what is the evidence?

A spaceship far from all other objects uses its thrusters to attain a speed of $\mathbf{1}\mathbf{×}{\mathbf{10}}^{\mathbf{4}}$m/s. The crew then shuts off the power. According to Newton's first law, what will happen to the motion of the spaceship from then on?

Why do we use a spaceship in outer space, far from other objects, to illustrate Newton's first law? Why not a car or a train? (More than one of the following statements may be correct.) ($\mathbf{1}$) A car or train touches other objects, and interacts with them. ($\mathbf{2}$) A car or train can't travel fast enough. ($\mathbf{3}$) The spaceship has negligible interactions with other objects. ($\mathbf{4}$) A car or train interacts gravitationally with the Earth. ($\mathbf{5}$) A spaceship can never experience a gravitational force.

Figure 1.55 shows several arrows representing vectors in the xy plane. (a) Which vectors have magnitudes equal to the magnitude of $\stackrel{¯}{\mathit{a}}$? (b) Which vectors are equal to $\stackrel{¯}{\mathit{a}}$?

Figure 1.55 shows several arrows representing vectors in the xy plane. (a) Which vectors have magnitudes equal to the magnitude of $\stackrel{â‡\P Ä}{a}$? (b) Which vectors are equal to $\stackrel{â‡\P Ä}{a}$?

A comet travels in an elliptical path around a star, in the direction shown in Figure 1.41. Which arrow best indicates the direction of the comet’s instantaneous velocity vector at each of the numbered locations in the orbit?