Review for Motion, Velocity, Acceleration, and Force Exam

**Coach K** **Review for Motion, Velocity, Acceleration, and Force Exam** Equations that will be provided on the exam: v = d/t a = (v2 - v1) / t a = 2d / t^2 F = ma Directions: Identify the following variables given in each word problem, then identify the variable you are solving for, the equation you would use, and the units the answer would be given in. For Example: A plane is descending at a velocity of 100   m/min. In a 12 minute period, the pilot slows its velocity of descent to 4 meters per min. What was the balloon's rate of deceleration?   a = (v2 - v1) / t 1. What distance is covered by a jet whose speed is 240 mph for 90 hours? v = 240 mph, t = 90 hr, d = ? units = miles v = d/t 2. A jogger ran 30 miles at a rate of 5 miles per hour. How long did it take the jogger to finish? d = 30 mi, v = 5 mph, t = ? units = hr v = d/t 3. Coach Kaufmann traveled to Texas, 1246 miles away, in 16 hours. What was Coach Kaufmann's velocity? d = 1246 mi, t = 16 hr, v = ? units = mph v = d/t 4. A student ran 181 cm in 4 seconds. How many cm per hour was he traveling? d = 181 cm, t = 4 s, v = ? units = cm/hr v = d/t 5. What force is needed to give an object with a mass of 25 kg an acceleration of 15 m/s²? m = 25 kg, a = 15 m/s², F = ? units = Newtons F = ma 6. A train had a rate of acceleration of 200 miles/hour² for 15 seconds (0.00416 hr). If his original velocity was 25 miles/hour, what was his final velocity? a = 200 mph², t = 0.00416 hr, v₁ = 25 mph, v₂ = ? units = mph a = (v₂ - v₁) / t 7. A cart that weighed 20 kg was pushed with a force of 50 kg m/s². What was the rate of the cart's acceleration? m = 20 kg, F = 50 kg m/s², a = ? units = m/s² F = ma 8. A horse accelerated from standing still at a rate of 14 feet/sec² for 125 feet. What was the time it took the horse to go the distance? a = 14 ft/sec², d = 125 ft, t = ? units = seconds a = 2d / t² **Directions: Define the following terms and give an example of their units** * Distance - total amount of space between two points * Displacement - amount of space between a start and end point * Velocity - how fast an object covers a distance * Speed - how fast an object covers a distance in a specific direction * Acceleration - a change in an object's velocity * Force - a push or pull on an object * Net Force - a sum of all forces exerted on an object **Directions: What do the following units represent? Use an F for Force, D for distance, T for time, V for velocity, or A for acceleration.** 9. 5 N - F 10. 14 m - D 11. 34 m/s - V 12. 10 kg m/s² - F 13. 6 s - T 14. 6 mi/hr - V 15. 4 m - D 16. 6 m/s² - A 17. 4 s - T 18. 15 cm/s² - A 19. 5 A 20. 15 cm/min/s - A 21. 19 days - T 22. sped up - A 23. deceleration - A 24. pushed - F 25. V 26. 7 km/hr/sec - A **Directions: Examine the diagram below and circle the answer that makes the statement true.** [Image of two people pulling a rope in opposite directions with 1000 Newtons of force each] 27. The forces above are (pushing/pulling) forces. 28. The forces shown above are (working together/opposite) forces. 29. The forces are (equal/not equal). 30. The forces are (balanced/not balanced). 31. The resulting net force is (1000N to the right/1000N to the left/zero). 32. There (is/is not) motion. [Image of a block being pulled by two forces: 5N to the right and 4N to the left] 33. Identify the net forces acting on the diagram above and draw their directions. [Image of a net force arrow pointing to the right with a value of 1N] 34. Find the acceleration of the 1 kg block and identify the direction it will move. [Image of a calculation: F = ma, a = F/m = 1 m/s^2] **Directions: Answer the following word problems. TO RECEIVE CREDIT!!! You must write the formula you are using, show work, AND write the correct units.** 1   1. v = d/t a = (v2 - v1) / t a = 2d / t^2 F = ma 35. What distance is covered by a jet whose speed is 240 miles per hour and flies for 90 hours? v = 240 mi/hr, t = 90 hr, d = ? v = d/t d = vt = (240 mi/hr)(90 hr) = 21,600 mi 36. A jogger ran 30 miles at a rate of 5 miles per hour. How long did it take the jogger to finish? d = 30 mi, v = 5 mph, t = ? v = d/t t = d/v = 30 mi / 5 mph = 6 hr 37. Coach Kaufmann traveled to Texas 1,246 miles away in 16 hours. What was Coach Kaufmann's velocity? d = 1246 mi, t = 16 hr, v = ? v = d/t v = 1246 mi / 16 hr = 77.88 mi/hr 38. A student ran 181 cm in 4 seconds. How many cm per hour was he traveling? d = 181 cm, t = 4 s, v = ? v = d/t v = 181 cm / 4 s = 45.25 cm/hr 39. A cart that weighed 20 kg was pushed with a force of 50 kg m/s². What was the rate of the cart's acceleration? m = 20 kg, F = 50 kg m/s², a = ? F = ma a = F/m = 50 kg m/s² / 20 kg = 2.5 m/s² a = 2d/t² 2d/a = t² t = √(2d/a) t = √(2*125/14) ≈ 4.22 s 43. A 5 kg block is pulled across a table by a horizontal force of 40 N with a frictional force of 8 N opposing the motion. Calculate the acceleration of the object.   F = 40 N f = 8 N m = 5 kg F - f = ma 40 - 8 = 5a 32 = 5a a = 32/5 = 6.4 m/s² 44. A plane is descending at a velocity of 10 meters per minute. In a 6 minute period, the pilot slows its velocity of descent to 2 meters per minute. What was the balloon's rate of deceleration?   (2 m/min - 10 m/min) / 6 min = -1.33 m/min² 45. Coach Kaufmann traveled to Texas 1,246 miles away in 15.57 hours. On the way home she got stuck behind a cop and the trip took 19.75 hours. What was Coach Kaufmann's average   velocity for the whole trip? (1246 mi / 15.57 hr) + (1246 mi / 19.75 hr) / 2 ≈ 80.03 mph 46. A bowling ball rolled with a force of 15 N accelerates at a rate of 3 m/sec². A second ball rolled with the same force accelerates 4 m/sec². What are the masses of the two balls?   F = 15 N a = 3 m/s² m₁ = ? F = 15 N a = 4 m/s² m₂ = ? F = ma m₁ = F/a = 15 N / 3 m/s² = 5 kg m₂ = F/a = 15 N / 4 m/s² = 3.75 kg 47. A 5 kg block is pulled across a table by a horizontal force of 40 N with a frictional force of 8 N opposing the motion. Calculate the acceleration of the object.   F = 40 N f = 8 N m = 5 kg F - f = ma 40 - 8 = 5a 32 = 5a a = 32/5 = 6.4 m/s² **Directions:** Read each scenario and label which of Newton's Laws best describes the situation. 48. As an ice skater pushes harder with his leg muscle, he begins to move faster. 3rd Law 49. When you paddle a canoe, the canoe goes forward. 3rd Law 50. The law of inertia is another name for which law? 1st Law 51. The equation F = ma is represented by this law. 2nd Law 52. According to this Law, a force is needed to change an object that is at rest. 1st Law [Image of a box being pushed by two people] **Question:** A 10 kg box is being pushed by two people. One person pushes with 6 N of force and the other pushes with 3 N of force in the same direction. Will they be able to move the box? Why or why not? (Use calculations to justify your answer.) F = ma 6 N + 3 N = (10 kg) * a 9 N = 10 kg * a a = 0.9 m/s²