KINEMATICS EXAM REVIEW

Define the following terms:

Vector

Scalar

Speed

Velocity

Constant velocity

At rest

Distance

Displacement

Acceleration

Relative Motion

Kinematics

Free fall

Acceleration due to gravity

Terminal velocity

Projectile

Peak height

Range

Acceleration due to gravity

Constant velocity

Parabolic trajectory

Inclined planes

Horizontally launched projectiles

Vector components

Answer the following conceptual questions:

1. What are the units of measurements for the following variables?

Variable SI UnitDisplacement/DistanceVelocity/SpeedAccelerationTimeMass

2. The slope of a position v. time graph represents what?3. The slope of a velocity v. time graph represents what?4. How can you find displacement on a velocity v. time graph?5. A soccer ball has 10x the mass of a golf ball. Both are dropped from a roof at the same time. Which one

hits the ground first?6. When an object is thrown upwards, its velocity at its maximum height is ____ m/s.7. A car is driving in circles at a constant speed. Is it accelerating?8. An object is traveling at a constant velocity. What is its acceleration?9. A fullback is running down the football field in a straight line. He starts at the 0-yard line at 0 seconds. At 1

second, he is on the 10-yard line; at 2 seconds, he is on the 20-yard line; at 3 seconds, he is on the 30-yard line; and at 4 seconds, he is on the 40-yard line. This is evidence that:a. He is acceleratingb. He is covering a greater distance in each consecutive secondc. He is moving at a constant velocity (on average)

10. A train travels east toward Chicago at 80 km/hr. A man on the train runs from the front of the train toward the rear of the train at 10 km/hr. As he runs, he carries a plate of fruit with him. He notices a giant spider on the plate and throws the plate away from him (toward the rear of the train) at 20 km/hr. The startled spider jumps toward the man at 5 km/hr. The instant after the spider jumps toward the man, how fast is the spider approaching Chicago?

11. The graph to the right gives the velocity of a particle moving on an x axis. What are (a) the initial and (b) the final directions of travel? (c) Does the particle stop momentarily? (d) Is the acceleration positive or negative? (e) Is it constant or varying?

12. Which of the following statements about acceleration are TRUE? List all that apply.a. Acceleration is a vector quantity.b. Accelerating objects MUST be changing their speed.c. Accelerating objects MUST be changing their velocity.d. An object which is slowing down has an acceleration.e. An object which is moving at constant speed in a circle has an acceleration.f. Acceleration is the rate at which the velocity changes.g. An object that is accelerating is moving fast.h. An object that is accelerating will eventually (if given enough time) be moving fast.i. An object that is moving rightward has a rightward acceleration.j. An object that is moving rightward and speeding up has a rightward acceleration.k. An object that is moving upwards and slowing down has an upwards acceleration.

13. A projectile has the least speed at what point in the path?14. Figure 14 shows three situations in which identical projectiles are launched (at the same level) at identical

speeds and angles. The projectiles do not land on the same terrain, however. Rank the situations according to the final speeds of the projectiles just before they land, greatest first.

15. Figure 15 shows three paths for a football kicked from ground level. Ignoring the effects of air, rank the paths according to (a) time of flight (b) initial vertical velocity (c) initial horizontal velocity and (d) initial speed.

16. You are on a train speeding past another train moving in the same direction on an adjacent parallel track. It appears the slower train is moving backwards. Why?

17. A cannonball is fired horizontally off a cliff twice. The first time, it is fired at an initial velocity of vo. The second time it is fired at twice that velocity. What effect does that have on the range?

18. Supposing a snowmobile is equipped with a flare launcher that is capable of launching a flare vertically (relative to the snowmobile). If the snowmobile is in motion and launches the flare and maintains a constant horizontal velocity after the launch, then where will the flare land (neglect air resistance)?

a. In front of snowmobile

b. Behind snowmobile

c. In the snowmobile

19. Suppose a rescue airplane drops a relief package while it is moving with a constant horizontal speed at an elevated height. Assuming that air resistance is negligible, where will the relief package land relative to the plane?

a. Below the plane and behind itb. Directly below the planec. Below the plane and ahead of it

20. Are projectiles in freefall? What is freefall? What is the only acceleration of any object in freefall?21. Three identical blocks take a different path to the ground from the same height. One is dropped. One slides

down a frictionless incline. One is projected horizontally. Which hits the ground first? Which has the greatest speed?

22. James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. If there is no air resistance, which has the greater splashdown speed when they hit the water?

Figure 14

Figure 15

23. A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory:a. both the velocity and the acceleration of the soccer ball are zero.b. neither the ball's velocity nor its acceleration are zero.c. the ball's acceleration is zero but its velocity is not zero.d. the ball's acceleration points upward.e. the ball's velocity points downward.

24. Look at this graph. Explain everything you can about the object’s motion.

Use the following graph of position vs. time to answer the following questions:

25. During which time interval(s) does the the car move at a constant speed?26. During which time interval(s) does the car not move? 27. During which time interval(s) is the car accelerating? 28. During which time interval(s) is the car moving backward?

Sketch a position-time graph for each of the following situations where an object is moving along a straight and level horizontal path.

29. An object at rest at x = 10m30. An object with constant positive velocity31. An object with constant negative velocity32. An object accelerating at a constant (uniform) rate

Sketch the velocity-time graphs for the following33. a city bus that is moving with a constant velocity34. a wheelbarrow that is speeding up at a uniform rate of speed while moving in the positive direction

a tiger that is speeding up at a uniform rate moving in the negative direction35. When is the average velocity of an object equal to the instantaneous velocity?

A) only when the velocity is increasing at a constant rateB) only when the velocity is decreasing at a constant rateC) when the velocity is constantD) always

E) never36. If the acceleration of an object is zero, then that object cannot be moving.

A) True B) False

37. A ball is thrown straight up, reaches a maximum height, then falls to its initial height. Which of the following statements about the direction of the velocity and acceleration of the ball as it is going up is correct?A) Both its velocity and its acceleration point upward.B) Its velocity points upward and its acceleration points downward.C) Its velocity points downward and its acceleration points upward.

D) Both its velocity and its acceleration points downward.

38. Which of the following position vs time and velocity vs time graphs represent an object at rest? (There could be more than one correct choice.)

39. The figure to the right shows a graph of the position x of two cars, C and D, as a function of time t. According to this graph, which statements about these cars must be true? (Mark all answers that are correct.)A) The magnitude of the acceleration of car C is greater than the magnitude of the acceleration of car D.B) The magnitude of the acceleration of car C is less than the magnitude of the acceleration of car D.C) At time t = 10 s, both cars have the same velocity.D) Both cars have the same acceleration.

E) The cars meet at time t = 10 s.

Solve the following problems showing proper work and box answers with units.

40. A motorboat traveling 4 m/s, East encounters a current traveling 7.0 m/s, North. What is the velocity of the boat relative to a stationary observer? If the width of the river is 80 m wide, how far downstream does the boat land?

41. A bus travels from El Paso to Fort Worth in 7.47 hrs with an average velocity of 130 km/hr to the East. What is the car’s displacement (answer in meters)?

42. A bus slows down uniformly from 75 km/hr to 0 km/hr in 21 sec. How far does it travel before stopping?43. A car’s velocity increases uniformly from 6.0 m/s to 20 m/s while covering 70 m.

a. Find the acceleration of the car. b. Find the time taken to make this motion

44. Rex throws his mother's crystal vase vertically upwards with an initial velocity of 26.2 m/s. Determine the height to which the vase will rise above its initial height.

45. A 5 m long slide at an angle of 20o is minding its own business in a playground, when a child slides down it. What is the acceleration of said child? Final velocity of said child?

46. A boy kicks a football from ground level with an initial velocity of 20 m/s at an angle of 30° above the horizontal. What is the horizontal distance to the point where the football hits the ground, if we neglect air resistance?

47. A raw egg is thrown horizontally out of the open window of a frat house. If its initial horizontal velocity is 20 m/s and it hits the ground 2.0 s later, at what height was it launched?