Physics I Practice Problems For Dummies (+ Free Online Practice). Dummies Consumer

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СКАЧАТЬ crawling velocity of 0.3 meters per second. If she accelerates at 2 meters per second per second, how long does it take her to reach her maximum velocity when she starts from rest?

       49. A plane’s takeoff speed is 300 kilometers per hour. If it accelerates at 2.9 meters per second per second, how long is it on the runway after starting its takeoff roll?

       50. You ride your bicycle at 10 meters per second and accelerate at −2.3 meters per second per second for 10 seconds. What is your final velocity?

Finding Displacement with Acceleration and Time

      51–54

       51. Starting from rest, you accelerate at 2 meters per second per second for 2 seconds to get up to full speed on your bicycle. How far do you travel during this time?

       52. A car accelerates northward at 4.0 meters per second per second over a distance of 30 meters. If it starts at rest, for how long does it accelerate?

       53. Starting from rest, a motorcycle rider covers 200 meters in 10 seconds. What was his acceleration?

       54. A tennis player serves a ball at 100 miles per hour. If the ball accelerates over a period of 0.05 seconds from essentially a standstill, how far (in meters) does the ball travel during its acceleration? One mile consists of 1,609 meters.

Finding Displacement with Acceleration and Velocities

      55–58

       55. You’re driving at 20 meters per second northbound and brake to slow to 10 meters per second. During that time, you cover 50 meters. What was your acceleration?

       56. You ski along at 3.0 meters per second, and your friend whizzes by at a greater speed. You have to accelerate at 2.0 meters per second per second for 20 meters to attain the same speed. At what speed was your friend skiing?

       57. A baseball pitcher throws a fastball at 90 miles per hour. He accelerates the ball over a distance of 2.0 meters. What is the acceleration of the ball?

       58. In a spaceship, you accelerate from 200 meters per second to 500 meters per second at 10 meters per second per second. How many kilometers do you travel during this acceleration?

Finding Acceleration with Displacement and Time

      59–62

       59. A speed skater accelerates from a standstill to full speed over a distance of 12 meters. If she takes 2.6 seconds to do this, what is the magnitude of her acceleration?

       60. Your car can accelerate at 3.4 meters per second per second. You are stopped at a red light and have 20 meters to accelerate onto the freeway when the light turns green. How long will it take you to accelerate over this distance?

       61. You’re driving at 18 meters per second when you apply the brake for 4 seconds. If the magnitude of your acceleration is 2.8 meters per second per second, how far did you travel in this time?

       62. A ferry boat is traveling east at 1.3 meters per second when the captain notices a boat in its path. The captain engages the reverse motors so that the ferry accelerates to the west at 0.2 meters per second per second. After 20 seconds of this acceleration, what is the boat’s position with respect to its initial position?

Finding Acceleration with Velocities and Displacement

      63–66

       63. A cheetah can accelerate from 0 miles per hour to 60 miles per hour in 20 meters. What is the magnitude of its acceleration?

       64. A speedboat can accelerate from an initial velocity of 3.0 meters per second to a final velocity that is 3 times greater over a distance of 42 meters. What is the magnitude of its acceleration?

       65. You drop a feather from your balcony, which is 4.5 meters above the ground. After falling 0.20 meters, it moves at the speed of 0.30 meters per second. What is the magnitude of its acceleration?

       66. A boat moving north at 2.3 meters per second undergoes constant acceleration until its speed is 1.2 meters per second northward. With respect to its initial position, its final position is 200 meters northward. What is its acceleration?

Finding Velocities with Acceleration and Displacement

      67–70

       67. A boat accelerates at 0.34 meters per second per second northward over a distance of 100 meters. If its initial velocity is 2.0 meters per second northward, what is its final velocity?

       68. A train brakes to a stop over a distance of 3,000 meters. If its acceleration is 0.1 meter per second per second, what is its initial speed?

       69. To pass another race car, a driver doubles his speed by accelerating at 4.5 meters per second per second for 50 meters. What are his initial and final speeds?

       70. From a position 120 meters above a pigeon, a falcon dives at 9.1 meters per second per second, starting from rest. After diving 25 meters, the falcon stops accelerating. What is the falcon’s speed when it strikes the pigeon?

Chapter 3

      Moving in a Two-Dimensional World

      The basic quantities you use to describe motion in two dimensions – displacement, velocity, and acceleration – are vectors. A vector is an object that has both a magnitude and a direction. When you have an equation that relates two vectors, you can break each vector into parts, called components. You end up with two equations, which are usually much easier to solve.

       The Problems You’ll Work On

      In this chapter on two-dimensional vectors and two-dimensional motion, you work with the following situations:

      ✓ Adding and subtracting vectors

      ✓ Multiplying a vector by a scalar

      ✓ Taking apart a vector to find its components

      ✓ Determining the magnitude and direction of a vector from its components

      ✓ Finding displacement, velocity, and acceleration in two dimensions

      ✓ Calculating the range and time of flight of projectiles

       What to Watch Out For

      While you zig and zag your way through the problems in this chapter, avoid running into obstacles by:

      ✓ Identifying the correct quadrant when finding the direction of a vector

      ✓ Finding the components before trying to add or subtract two vectors

      ✓ Breaking the displacement, velocity, and acceleration vectors into components to turn one difficult problem into two simple problems

      ✓ Remembering that the vertical component of velocity is zero at the apex

      ✓ СКАЧАТЬ