A projectile MUST____. List all that apply. a) experience a net downward force b) have a constant speed c) be accelerating d) be changing its velocity e) be moving downward f) have a horizontal motion in addition to a vertical

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  1. physics

    A projectile MUST____. List all that apply. a) experience a net downward force b) have a constant speed c) be accelerating d) be changing its velocity e) be moving downward f) have a horizontal motion in addition to a vertical motion
  2. physics

    A projectile MUST____. List all that apply. a) experience a net downward force b) have a constant speed c) be accelerating d) be changing its velocity e) be moving downward f) have a horizontal motion in addition to a vertical motion
  3. physics

    Consider a car making a turn at a constant speed a) is the net force on the car zero? Why? b) Is the velocity of the car constant? Why? c) Is the car accelerating? Why? a)no it's not zero. Is it because it is experianceing a net force,, which is centripetal force because it is...
  4. physics

    A 800·kg elevator is attached to a cable whose tension is 7800·N. Which of the following statements could describe the motion of the elevator? Choose all that apply. slowing down as it moves upward moving upward at constant speed speeding up as it moves downward slowing down...
  5. Physics

    a packing ccrate slides down an incline ramp at constant velocity. Thus we can deduce that a) a frictional force is acting on it b) a net downward force is acting on it c) it may be accelerating d) it is not acted on by appreciable gravitational force with a constant velocity ...
  6. Physics

    An elevator and its load have a combined mass of 1600 kg. Find the tension in the supporting cable when the elevator, originally moving downward at 12 m/s is brought to rest with constant acceleration in a distance of 42m. T=w which means that T=mg. My book said that the ...
  7. Can you check my answer - Physics

    A balloonist drops an apple weighing 1.5 N over the side of the balloon's gondola. As it falls and increases speed, the drag force from the air upward on it increases. When the upward force is 0.7 N, what is the direction and magnitude of the net force on the apple? 9.8 N ...
  8. physics

    An elevator is being lifted up an elevator shaft at a constant speed by a steel cable. All fricional effects are negligible. In this situation,forces on the elevator are such that?: A.the upward force by the cable is greater than the downward force of gravity B. the upward ...
  9. physics

    an 800 N person stands on a scale in an elevator. What is his apparent weight when the elevator is accelerating upward at 2 m/s^2? B) what5 is his apparent weight when the elevator is acc. downward at 2m/s^2? c) what is his apparent weight when the elevator is moving downward ...
  10. Science

    1. A balloonist drops an apple weighing 1.5 N over the side of the balloon's gondola. As it falls and increases speed, the drag force from the air upward on it increases. When the upward force is 0.7 N, what is the direction and magnitude of the net force on the apple? 9.8 N ...
  11. Physics

    Newton's second law states that if an object has zero acceleration, the net force acting on it is zero. My question is if you have an object at constant acceleration moving downward is there a net force being applied to it? Does constant acceleration= zero net force? Yes, for ...
  12. Science

    4: Which of the following is true of an object in a circular motion at a constant speed? A: The net force on the object is zero B: The object is not accelerating as the speed of the object remains the same C:the object is accelerating as the direction of the object is changing...
  13. Physics

    A chain composed of four identical links is suspended by a rope and does not move. How many force vectors would be drawn on the free body diagram of each link and which direction would they point? My answer: ---------- FIRST LINK (top): Upward force from rope (tension), ...
  14. physics

    An electron ( mass = 9.11×10−31 kg) leaves one end of a TV picture tube with zero initial speed and travels in a straight line to the accelerating grid, which is 1.85 cm away. It reaches the grid with a speed of 2.95×10^6 m/s . (You can ignore the gravitational force ...
  15. Physics

    If a car is moving on a highway at 70 kilometers per hour, going south, and then turns to travel 70 kilometers per hour east, what happens to its speed and velocity? Speed is constant, velocity is constant. Speed is changing, velocity is constant. Speed is changing, velocity ...
  16. Physicss

    Chapter 4, Problem 40 A 94.9-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 2.30 m/s^2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1....
  17. Physics

    A 72.0-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.80 m/s2, N (b) moving upward at a constant speed, and N (c) accelerating downward with an acceleration of 1.30 m/s2? N I just ...
  18. Physics

    Chapter 4, Problem 36 Incorrect. A 77.2-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.66 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an ...
  19. Physics

    A 97.0-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.70 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.80 m/s2?
  20. Physics

    74.0-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.10 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.00 m/s2?
  21. physics

    A 84.5-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.93 m/s 2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.57 m/s2?
  22. Physics

    A 96.6-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.79 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.14 m/s2?
  23. physics

    A 72.2-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.53 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.44 m/s2?
  24. physics

    You are driving in your car and you apply a constant force to your brake pedal. Which of the following are changing? (Ignore air resistance) a. Speed b. Velocity c. Acceleration d. Speed and Velocity e. All of the above
  25. Physics

    Is a net force being applied to an object when the object is moving downward under the following conditions? a) with a constant acceleration of 9.80 m/s2 yes no not enough information to decide Explain. (b) with a constant velocity of 9.80 m/s yes no not enough information to ...
  26. physics

    A skydiver, who weighs 650 N, is falling at a constant speed with his parachute open. Consider the apparatus that connects the parachute to the skydiver to be part of the parachute. The parachute pulls upward with a force of 620 N. Consider the skydiver and parachute to be a ...
  27. Physics

    A weather balloon is released at an altitude of 500m. The force of gravity on the balloon is 21.1n. The lift force provided by the atmosphere is 18.7n. Which of the following is true about the balloon? a. The balloon rises at constant velocity. b. the net force on the balloon ...
  28. PHYSICS

    1. A sound with a frequency of 261.6 Hz travels through water at a speed of 1435 m/s. What is the wavelength of the wave? a. 1.83 x 10 -1 m b. 3.753 x 10 5 m c. 5.486 m d. You cannot tell from the given information 2. A 23.0 kg mass of is accelerated at + 4.50 m/s2. What is ...
  29. Physics

    A 76.6-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.94 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.15 m/s2? I've already ...
  30. Help Physics

    A child with a mass of 39 kg stands on a spring scale inside an elevator. For each of the scenarios below, draw a force diagram of the forces acting on the child and calculate the reading of the scale in newtons. (a) The elevator is at rest. _______ N (b) The elevator is ...
  31. physics

    a 75kg person is standing on a scale in an elevator, the scale gives a readout in newtons(you have to use a free body diagram)determine the reading on the scale in newtons in each of the following situations, when the elevator is not moving, the elevator is moving upward at 2 ...
  32. physics

    An elevator is moving upward with a speed of 11 m/s. Three seconds later, the elevator is still moving upward, but its speed has been reduced to 5.0 m/s. What is the average acceleration of the elevator during the 3.0 s interval? a.5.3 m/s2, upward b.2.0 m/s2, upward c.5.3 m/...
  33. physics

    The cable of a 1800-kg elevator has broken, and the elevator is moving downward at a steady speed of 1.6 m/s. A safety braking system that works on friction prevents the downward speed from increasing. a. at what rate does mechanical energy turn into thermal energy. I found ...
  34. physics

    The cable of a 1800-kg elevator has broken, and the elevator is moving downward at a steady speed of 1.6 m/s. A safety braking system that works on friction prevents the downward speed from increasing. a. at what rate does mechanical energy turn into thermal energy. I found ...
  35. Physics

    A force of gravity pulls downward on a book on a table what force prevents the book from accelerating downward?
  36. Physics(Please respond)

    A 79.2-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is (a) accelerating upward with an acceleration of 1.92 m/s2, (b) moving upward at a constant speed, and (c) accelerating downward with an acceleration of 1.89 m/s2 I was going to ...
  37. physics

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 9.7-kg projectile from rest to a speed of 6.5 × 103 m/s. The net force accelerating the projectile is 8.0 × 105 N. How much ...
  38. physics

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 7.0 kg projectile from rest to a speed of 4.0 x 103 m/s. The net force accelerating the projectile is 4.9 x 105 N. How much ...
  39. physicsh

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 4.8-kg projectile from rest to a speed of 3.9 103 m/s. The net force accelerating the projectile is 4.8 105 N. How much time is...
  40. science

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 4.8-kg projectile from rest to a speed of 3.9 103 m/s. The net force accelerating the projectile is 4.8 105 N. How much time is...
  41. PHYSICS

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 8.9-kg projectile from rest to a speed of 4.2 × 103 m/s. The net force accelerating the projectile is 1.4 × 105 N. How much ...
  42. Physics

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 1.9-kg projectile from rest to a speed of 5.1 × 103 m/s. The net force accelerating the projectile is 8.6 × 105 N. How much ...
  43. math

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 7.9-kg projectile from rest to a speed of 2.8 × 103 m/s. The net force accelerating the projectile is 6.7 × 105 N. How ...
  44. physics

    a 95-kg person stands on a scale in an elevator. What is the apparent weight when the elevator is: (A) accelerating upward with an acceleration of 1.8 m/s^2 (answer 1.1 * 10^3 N) (B) moving upward at a constant speed (answer 931 N) (C) accelerating downward with an ...
  45. physics

    Scientists are experimenting with a kind of gun that may eventually be used to fire payloads directly into orbit. In one test, this gun accelerates a 4.8-kg projectile from rest to a speed of3.9 103 m/s. The net force accelerating the projectile is 4.8 105 N. How much time is ...
  46. physics

    A Chinook salmon has a maximum underwater speed of 3.0 m/s, and can jump out of the water vertically with a speed of 4.8 m/s. A record salmon has a length of 1.5 m and a mass of 62 kg. When swimming upward at constant speed, and neglecting buoyancy, the fish experiences three ...
  47. physics

    Hi I need help to figure out if these situations are possible or impossible thank you. constant velocity, non-zero net force constant speed, non-zero net force velocity to the left, net force to the right decreasing velocity, increasing magnitude of net force
  48. physics

    An inquisitive physics student and mountain climber climbs a 50.0 m cliff that overhangs a calm pool of water. He throws two stones vertically downward, 1.00 s apart, and observes that they cause a single splash. The first stone has an initial speed of 2.08 m/s downward. (a) ...
  49. Math

    A projectile is fired straight up from a cliff which is 200 feet above ground with an initial velocity of 220 ft/sec. Assume that the only force affecting the projectile during flight is from gravity which produces a downward acceleration 32 ft/sec^2. Find an equation from the...
  50. Physics

    A projectile is fired straight up from a cliff which is 200 feet above ground with an initial velocity of 220 ft/sec. Assume that the only force affecting the projectile during flight is from gravity which produces a downward acceleration 32 ft/sec^2. Find an equation from the...
  51. Physics

    A roller-coaster car has a mass of 1170 kg when fully loaded with passengers. As the car passes over the top of a circular hill of radius 16 m, its speed is not changing. (a) What are the magnitude and direction of the force of the track on the car at the top of the hill if ...
  52. Physics

    Hi guys, need help with this problem for physics and im having trouble visualizing it. Kathy and mountain climber climbs a 55.0 m cliff that overhangs a calm pool of water. He throws two stones vertically downward, 1.00 s apart, and observes that they cause a single splash. ...
  53. Math

    You're on a skateboard, moving very fast but at a constant speed. Are you accelerating? Explain. Lara Claims that if an object is accelerating, it must be moving. She also claims that if an object is not accelerating, it must be at rest. Is lara correct? Explain. Is a dog ...
  54. science

    A 50 kg skier is pulled up a frictionless ski slope that makes an angle of 8 degrees with the horizontal by holding onto a tow rope that moves parallel to the slope. Determine the magnitude of the force of the rope on the skier at an instant when a) the rope is moving with a ...
  55. phsyic's

    If an object is moving at a constant acceleration then it could NOT be.... A. changing its direction B. moving in a straight line C. Moving at a constant speed D. Moving at a constant velocity ((D is what I think it is))
  56. PHYSICS

    A factory worker pushes a 30.7 crate a distance of 4.0 along a level floor at constant velocity by pushing downward at an angle of 31 below the horizontal. The coefficient of kinetic friction between the crate and floor is 0.26. What magnitude of force must the worker apply to...
  57. Physics

    A 1200 kg car pulls an 820 kg trailer over a rough road. The force of friction acting on the trailer is 650 N [backwards]. Calculate the force that the car exerts on the trailer if (a) the trailer is moving at a constant velocity of 30 km/h [forward] (b) the trailer is moving ...
  58. Physics

    A bicyclist moving at a constant speed takes 10.0 seconds to travel 500 meters down a path inclined 30.0° downward from the horizontal. What is the vertical velocity of this motion?
  59. Physics

    A ball is thrown vertically upward from the ground with a speed of 36.0 m/s.Suppose the acceleration of gravity were only 2.00 m/s^2 instead of 9.80 m/s^2 a)At what time does it have a velocity of 12.0 m/s upward? b)At what time does it have a velocity of 12.0 m/s downward? c)...
  60. AP Physics

    Hi! I'm supposed to derive an algebraic formula to solve for the acceleration using one of the linear kinematics formulas of an elevator with a person inside that begins to accelerate from rest moving downward. If it travels a know distance, d, in reaching its max downward ...
  61. Phys

    Three blocks on a frictionless horizontal surface are in contact with each other. A force F is applied to block A (mass mA). (a) Draw a free body diagram for each block. I've drawn it and it looks like this, but I'm not sure if I'm including everything. ^normal force F-->|...
  62. physics

    true or false If a net force acts on an object, the object's speed will change. An object's velocity will change if a net force acts on the object. If two object have the same acceleration, they are under the influence of equal forces. The net force which acts on an object ...
  63. physics

    A person in a stationary, non-moving elevator drops a coin and it reaches the floor 0.6 seconds later. Now he repeats the experiment with the elevator moving. Would the coin reach the floor in less time same time or more time, if it were dropped when the elevator was: ...
  64. Physics

    A body of mass m falls from rest through the air. A drag force D = bv^2 opposes the the motion of the body. The acceleration due to gravity is g. A) What is the initial downward acceleration of the body? B) After some time the speed of the body approaches a constant value. ...
  65. Physics

    A 124-kg balloon carrying a 22-kg basket is descending with a constant downward velocity of 25.2 m/s A 1.0-kg stone is thrown from the basket with an initial velocity of 11.7 m/s perpendicular to the path of the descending balloon, as measured relative to a person at rest in ...
  66. Physics

    An object moves in a circular path with constant speed. Is the object's velocity constant? Is its acceleration constant? Please explain. From what I've learned in my 8th grade science class, when velocity changes is when the direction or speed changes. So if it is moving in a ...
  67. Physics

    A skydiver, who weighs 650 N, is falling at a constant speed with his parachute open. Consider the apparatus that connects the parachute to the skydiver to be part of the parachute. The parachute pulls upward with a force of 620 N. You have to consider the skydiver and ...
  68. Physics

    A worker pushes horizontally on a 25 kg crate resting on ground level. The coefficients of static and kinetic friction are 0.4 and 0.3.? a) How much force must he apply to start the crate moving? b) After the crate has stereo moving, how much force must he apply to move the ...
  69. physics

    under the influence of its drive force, snowmobile is moving at constant velocity along a horizontal patch of snow. When drive force is shut off, snowmobile coasts to a halt. a) During the coasting phase, what is the net external force acting on the snowmobile b) How does work...
  70. college physics

    A 52.2 kg parachutist lands moving straight downward with a speed of 3.75 m/s. If the parachutist comes to rest with constant acceleration over a distance of 0.794 m, what force does the ground exert on her?
  71. Physics

    5) You are pushing a 55 kg refrigerator along at a constant speed of 1.5 m/s using an applied force of 250 N when the floor type changes from tile to carpet. The carpet has a coefficient of static friction of 0.62 and a coefficient of kinetic friction of 0.54. Are you pushing ...
  72. Physical Science

    1.Instantaneous speed is measured B. when the object reaches its destination. C. at a particular instant. D. over the duration of the trip. 2. A ball is rolled uphill a distance of 5 meters before it slows, stops, and begins to roll back. The ball rolls downhill 9 meters ...
  73. Physics

    A trapeze artist, starting from rest, swings downward on the bar, lets go at the bottom of the swing, and falls freely to the net. An assistant, standing on the same platform as the trapeze artist, jumps from rest straight downward. Friction and air resistance are negligible...
  74. physics

    If a car is accelerating downhill under a net force of 3,674N, what force must the brakes exert to cause the car to have a constant velocity?
  75. physics

    if a car is accelerating downhill under a net force of 3674 N, what force must the brakes exert to cause the car to have a constant velocity?
  76. physics

    If a car is accelerating downhill under a net force of 3674 N, what force must the brakes exert to cause the car to have a constant velocity?
  77. 12th grade

    If a car is accelerating downhill under a net force of 3674, what additional force would cause the car to have a constant velocity?
  78. Physics

    What is an equilibrant? (Points : 1) an object that has zero net force acting on it two chemical reactions proceeding at the same rate in opposite directions a force that makes the net force on an object zero a force in the same direction as the net force Question 2. 2. How is...
  79. physics

    A 124- balloon carrying a 22- basket is descending with a constant downward velocity of 27.4 A 1.0- stone is thrown from the basket with an initial velocity of 20.0 perpendicular to the path of the descending balloon, as measured relative to a person at rest in the basket. The...
  80. class

    WHAT DOES A 138 N ROCK WEIH IF IT IS ACCELERATING UPWARD AT 12 M/S DOWNWARD AT3.5 M/S . C WHAT WOULD BE THE ANSWERS TO PARTS (A)AND (B) IF THE ROCK HAD A MASS OF138 Kg WHAT WOULD BE THE ANSWERS TO PARTS A AND B IF THE ROCK WERE MOVING WITH A CONSTANT UPWARD VELOCITY OF 23 M/S?
  81. physics

    You push a 320 N trunk up a 20.0° inclined plane at a constant velocity by exerting a 213 N force parallel to the plane's surface. (a) What is the component of the trunk's weight parallel to the plane? (b) What is the sum of all forces parallel to the plane's surface? (c) ...
  82. Physics

    If a young girl is in a truck that is rolling down a hill with a force of 8765 N, what force must the brakes apply on the truck to have the truck roll at a constant speed? Would she have to apply more than 8765 N or less than 8765 N to get the truck to stop? My thoughts are, ...
  83. multiple choices

    Which of the following is accelerating? An object moving with a constant velocity. An object moving along a curve. None An object moving on a straught line with a constant speed.
  84. Science

    1. The line on the graph below represents an object that is: A: Moving at a constant speed B: Increasing its speed C: Decreasing it's speed D: Not moving at all 2. To determine the acceleration of an object moving in a straight line, you must calculate the change in its speed ...
  85. Physics

    A factory worker pushes a 32.0 kg crate a distance of 4.9 m along a level floor at constant velocity by pushing downward at an angle of 32 ∘ below the horizontal. The coefficient of kinetic friction between the crate and floor is 0.25. What magnitude of force must the ...
  86. physics

    The cable of a 1800-kg elevator has broken, and the elevator is moving downward at a steady speed of 1.6 m/s. A safety braking system that works on friction prevents the downward speed from increasing. a. speed of boat when leaves ramp (assume that engine turned off once boat ...
  87. science physics

    A cyclist is moving to the right at a constant speed. when he applies brakes what will happen? a -net force will be to left b- net force will be to right c- acting net force will be zero d -inertia will stop him
  88. Physics

    Analyze the flight of a projectile moving under the influence of gravity (mg) and linear, i.e., laminar- flow drag (fD = bv, with b > 0 constant). Neglect \Phase I"; assume the projectile is launched from the origin at speed v1 and angle 1 above the horizontal. WARNING: ...
  89. Physics

    An elevator is initially moving upward at a speed of 11.04 m/s. The elevator experiences a constant downward acceleration of magnitude 3.84 m/s2 for 3.06 s. (a) Find the magnitude and direction of the elevator's final velocity. (b)How far did it move during the 3.06 s interval?
  90. Physics 221

    1. throughout a time interval, while the speed of a particle increases as it moves along the x axis, its velocity and acceleration might be: A. positive and negative, respectively B. negative and positive, respectively C. negativa and negative, respectively D. negative and ...
  91. Physics

    I have this problem about drawing graphs. For the following 6 situations, sketch a graph of velocity vs. time. A cart is moving to the right on a horizontal surface while a constant net force of 3 newtons acts on it to the left> The force acting on the cart stops after a ...
  92. Physics/Math

    A 1.50 kg snowball is fired from a cliff 13.5 m high with an initial velocity of 14.0 m/s, directed 41.0° above the horizontal. (a) Using energy techniques, rather than techniques of Chapter 4, find the speed of the snowball as it reaches the ground below the cliff. >>&...
  93. physics

    A courier is delivering a 5kg package to an office high in a tall building. (a) What upwards force does the courier apply to the package when carrying it horizontally at a constant velocity of 2m/s into the building? (b) The courier uses the elevator to reach the office. While...
  94. physics

    A 124- balloon carrying a 22- basket is descending with a constant downward velocity of 16.3 A 1.0- stone is thrown from the basket with an initial velocity of 18.7 perpendicular to the path of the descending balloon, as measured relative to a person at rest in the basket. The...
  95. physics

    A crate is pulled to the right with a force of 84.5 N, to the left with a force of 116.5 N, upward with a force of 685.7 N, and downward with a force of 242 N. What is the net external force in the x direction?
  96. Physics

    (10 points) 3. Use your data from Part 3 and Newton’s laws to explain why the force meter measures a force if the cart is moving at a constant velocity. The forces acting on the cart are the applied force (FA), the force of friction (Ff), weight (Fg) and the normal force (FN...
  97. Science-Enr. Phys.

    A box of books weighing 325 N moves at a constant velocity across the floor when the box is pushed with a force of 425 N exerted downward at an angle of 35.2 degrees below the horizontal. Fink Mu,k between the box and the floor. There have been several of this type of question...
  98. Physics

    A 75 kg person escapes from a burning building by jumping from a window 25 m above a catching net. Assuming that air resistance exerts a 95 N force on the person during the fall, determine the person's velocity just before hitting the net. My main problem is finding the force ...
  99. physics

    A crate is pulled to the right with a force of 93.5 N, to the left with a force of 116.8 N, upward with a force of 658.1 N, and downward with a force of 248.6 N. What is the net external force in the x direction? Answer in units of N
  100. Physics

    Sorry if it is alot of questions 1. A crate falls from an airplane flying horizontally at an altitude of 2000 m. Neglecting air resistance, about how long will the crate take to strike the ground? a. 10 seconds b. 20 seconds c. 400 seconds d. 100 seconds 2. An object is ...
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