Fisik
Páginas: 2 (370 palabras)
Publicado: 15 de febrero de 2010
The speed of sound in air is 331 m/s. during the next thunderstorm, try to estimate your distance from a lightning bolt by measuring the time lag between the flash and the thunderclap. You can ignorethe time it takes for the light flash to reach you. Why?
3. if the average velocity of an object is zero in some time interval, what can you say about the displacement of the object for theinterval?
5. if an object’s average velocity is nonzero over some time interval, does this mean that is instantaneous velocity is never zero during the interval? Explain your answer.
7. if the velocity of aparticle is nonzero, can its acceleration be zero? explain.
9. two cars are the moving in the same direction in parallel lanes along highway. At some instant, the velocity of car A exceeds thevelocity of car B. does this mean that the acceleration of A is greater than that of B? explain
11. consider the following combinations of signs and values for velocity and acceleration of a particle withrespect to a one dimensional x axis
13. a stone is thrown vertically upward from the roof of a building. Does the position of the stone depend on the location chosen for the origin of the coordinatesystem? Does the stone’s velocity depend on the choice of origin? Explain your answers
15.a student at the top a building of height h throws one ball upward with a speed of a v i and then throws asecond ball downward with the same initial speed vi. how do the final velocities of the balls compare when they reach the ground?
17. you drop a ball from a window on an upper floor of a building. Itstrikes the ground with speed v. you now repeat the drop, but you have a friend down on the street who throws another ball upward at the speed v. your friend throws the ball upward at exactly the sametime that you drop yours from the window. At some location, the balls pass each other. Is this location at the halfway point between window and ground, above this point, or below this point?
3. if the average velocity of an object is zero in some time interval, what can you say about the displacement of the object for theinterval?
5. if an object’s average velocity is nonzero over some time interval, does this mean that is instantaneous velocity is never zero during the interval? Explain your answer.
7. if the velocity of aparticle is nonzero, can its acceleration be zero? explain.
9. two cars are the moving in the same direction in parallel lanes along highway. At some instant, the velocity of car A exceeds thevelocity of car B. does this mean that the acceleration of A is greater than that of B? explain
11. consider the following combinations of signs and values for velocity and acceleration of a particle withrespect to a one dimensional x axis
13. a stone is thrown vertically upward from the roof of a building. Does the position of the stone depend on the location chosen for the origin of the coordinatesystem? Does the stone’s velocity depend on the choice of origin? Explain your answers
15.a student at the top a building of height h throws one ball upward with a speed of a v i and then throws asecond ball downward with the same initial speed vi. how do the final velocities of the balls compare when they reach the ground?
17. you drop a ball from a window on an upper floor of a building. Itstrikes the ground with speed v. you now repeat the drop, but you have a friend down on the street who throws another ball upward at the speed v. your friend throws the ball upward at exactly the sametime that you drop yours from the window. At some location, the balls pass each other. Is this location at the halfway point between window and ground, above this point, or below this point?
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