physics test 2
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____ 1. Which of the following situations represents a negative displacement? (Assume positive position is measured vertically upward along a y-axis.)
a. / A cat stands on a tree limb.b. / A cat jumps from the ground onto a tree limb.
c. / A cat jumps from a lower tree limb to a higher one.
d. / A cat jumps from a tree limb to the ground.
____ 2. Which of the following units is the SI unit of velocity?
a. / meter / c. / meter per secondb. / meter·second / d. / second per meter
____ 3. Suppose you are given a velocity versus time graph. The slope of a line of this graph describes what quantity?
a. / acceleration / c. / instantaneous velocityb. / displacement / d. / position
____ 4. What is the SI unit of acceleration?
a. / m/s / c. / m/sb. / m/s / d. / m·s
____ 5. A baseball catcher throws a ball vertically upward and catches it in the same spot as it returns to the mitt. At what point in the ball’s path does it experience zero velocity and nonzero acceleration at the same time?
a. / midway on the way upb. / at the top of its path
c. / the instant it leaves the catcher’s hand
d. / the instant before it arrives in the catcher’s mitt
____ 6. When there is no air resistance, objects of different masses dropped from rest
a. / fall with equal accelerations and with equal displacements.b. / fall with different accelerations and with different displacements.
c. / fall with equal accelerations and with different displacements.
d. / fall with different accelerations and with equal displacements.
The driver of a car traveling at 110 km/h slams on the brakes so that the car undergoes a constant acceleration, skidding to a complete stop in 4.5 s.
____ 7. What is the average acceleration of the car during braking?
a. / 10.41 m/s2 / c. / 6.9 m/s2b. / 14.15 m/s2 / d. / 2.4 m/s2
____ 8. If the car skids in a straight line for the entire length of the stopping distance, how long are its skid marks?
a. / 7.0´101 m / c. / 2.1´102 mb. / 1.4´102 m / d. / 2.5´102 m
____ 9. Identify the following quantities as scalar or vector: the mass of an object, the number of leaves on a tree, wind velocity.
a. / vector, scalar, scalar / c. / scalar, vector, scalarb. / scalar, scalar, vector / d. / vector, scalar, vector
____ 10. A car travels down a road at a certain velocity, vcar. The driver slows down so that the car is traveling only half as fast as before. Which of the following is the correct expression for the resulting velocity?
a. / 2vcar / c. / –vcarb. / vcar / d. / –2vcar
____ 11. An ant on a picnic table travels 30 cm eastward, then 25 cm northward, and finally 10 cm at a 45 degree angle northwest to the horizonal . What is the magnitude of the ant’s displacement relative to its original position?
a. / 39.4 cm northwest / c. / 46.1 cm northeastb. / 46.1 cm northwest / d. / 39.4 cm northeast
____ 12. In a coordinate system, a vector is oriented at angle q with respect to the x-axis. The x component of the vector equals the vector’s magnitude multiplied by which trigonometric function?
a. / cos q / c. / sin qb. / cot q / d. / tan q
____ 13. In a coordinate system, a vector is oriented at angle q with respect to the x-axis. The y component of the vector equals the vector’s magnitude multiplied by which trigonometric function?
a. / cos q / c. / sin qb. / cot q / d. / tan q
____ 14. Find the resultant of these two vectors: 2.00 ´ 10 units due east and 4.00 ´ 10 units 30.0° north of west.
a. / 300 units, 29.8° north of west / c. / 546 units, 59.3° north of westb. / 581 units, 20.1° north of east / d. / 248 units, 53.9° north of west
The figure above (figure 3:1) shows the path of a ball tossed from a building. Air resistance is ignored.
____ 15. At what point of the ball’s path shown in the figure above(figure 3:1) is the vertical component of the ball’s velocity zero?
a. / A / c. / Cb. / B / d. / D
____ 16. In the figure above,(figure 3:1) the magnitude of the ball’s velocity is least at location
a. / A. / c. / C.b. / B. / d. / D.
____ 17. In the figure above,(figure 3:1) the magnitude of the ball’s velocity is greatest at location
a. / A. / c. / C.b. / B. / d. / D.
____ 18. In the figure above,(figure 3:1) the horizontal component of the ball’s velocity at A is
a. / zero.b. / equal to the vertical component of the ball’s velocity at C.
c. / equal in magnitude but opposite in direction to the horizontal component of the ball’s velocity at D.
d. / equal to the horizontal component of its initial velocity.
____ 19. In the figure above,(figure 3:1) at which point is the ball’s speed about equal to the speed at which it was tossed?
a. / A / c. / Cb. / B / d. / D
____ 20. A track star in the long jump goes into the jump at 12 m/s and launches herself at 20.0° above the horizontal. What is the magnitude of her horizontal displacement?
a. / 4.6 m / c. / 13 mb. / 9.2 m / d. / 15 m
____ 21. A rock is thrown straight upward with an initial velocity of 24.5 m/s where the downward acceleration due to gravity is 9.81 m/s2. What is the rock's displacement after 1.00 s?
a. / 9.81 m / c. / 24.5 mb. / 19.6 m / d. / 29.4 m
____ 22. A rock is thrown straight upward with an initial velocity of 19.6 m/s where the downward acceleration due to gravity is 9.81 m/s2. What time interval elapses between the rock's being thrown and its return to the original launch point?
a. / 4.00 s / c. / 8.00 sb. / 5.00 s / d. / 10.0 s
____ 23. A tourist accidentally drops a camera from a 40.0 m high bridge. If g = 9.81 m/s2 and air resistance is disregarded, what is the speed of the camera as it hits the water?
a. / 28.0 m/s / c. / 56.0 m/sb. / 31.0 m/s / d. / 784 m/s
____ 24. A person jumps at 12 m/s and launches themselves at 30.0° above the horizontal. What is the magnitude of her vertical displacement?
a. / 10 m / c. / 1.2 mb. / 7.2 m / d. / 1.8 m
____ 25. A track star in the long jump goes into the jump at 12 m/s and launches herself at 30.0° above the horizontal. What is the magnitude of her total time in the air?
a. / 10 s / c. / 0.6 sb. / 1.5 s / d. / 1.2 s
Short Answer
26. If a runner moves from a positive position to a negative position, is the runner’s displacement negative or positive? Explain.
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27. The displacement, -2.0 m north, represents a positive displacement in which direction?
Problem 6 points each show your work for full credit
28. A dog walks 24 steps north and then walks 55 steps west to bury a bone. If the dog walks back to the starting point in a straight line, how many steps will the dog take and in which direction will the dog walk? Find the magnitude of the net displacement. remember the angle and direction.
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29. Given a cannon sitting on the edge of a cliff. If the cannon fires a cannon ball at 50 m/s horizonally and the cannon ball lands 200 meters from the edge of the bottom of the cliff how high is the cliff?
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30. Given a cannon sitting on the edge of a 100 meter high cliff. If the cannon fires a cannon ball at 100 m/s at an angle of 45 degrees to the horizonally how far from the bottom of the cliff will the cannon ball land?
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31. A model rocket flies horizontally off the edge of the cliff at a velocity of 50.0 m/s. If the canyon below is 100.0 m deep, how far from the edge of the cliff does the model rocket land?