Arianna Srb
Chapter 2
8. The two controls of a car that cause a change in speed are the gas pedal and break pedal. The
steering wheel causes only a change in velocity because is changes the direction of a car.
9. Acceleration is the quantity that describes how quickly you change how fast your traveling, or
how quickly you change directions.
10. Acceleration is the rate at which velocity changes
11. The acceleration of a car that travels in a straight line in a constant speed of 100 km/h is zero.
Since the change in velocity is zero, then acceleration is also zero.
12. Acceleration= change in velocity/ time. This cars acceleration equals 10 km/h/s.
16. If gravity is 9.8, then for a freely falling object dropped from res the instantaneous speed at
the end of the fifth second is 49 m/s, and for the end of the sixth second is 58.8 m/s.
17. At the end of any elapsed time for a freely falling object dropped at rest, the acceleration with
remain at a constant of 9.8 m/s.
18. When you toss a ball upward, the change in speed on the way up and down will remain at a
constant of 9.8 m/s.
22. The slope on a distance versus time graph represents velocity.
23. The slope on a velocity versus time graph represents acceleration.
24. Air resistance increases the acceleration of a freely falling object.
Chapter 3
3. If a vector that is 1 cm long represents a velocity of 10km/h, then a vector of 2 cm represents a
velocity of 20km/h.
8. In the absence of air resistance, the horizontal component of velocity remains constant because
in gravitational force, there is no horizontal component.
13. Without air resistance, if you throw a ball straight up at the speed of 20m/s, it will be moving
at 20m/s when you catch it.
15. A projectile that continuously falls around the earth is an earth satellite.
34. if a projectile is launched straight up at 141m/s, at the top of its trajectory, it will still be
moving 141m/s.
38. We can say a satellite is falling because since gravity is not acting upon it, it is falling under
the straight-line tangent.