9.1 Acceleration Check Your Understanding All Questions

1.    To put it in reverse or put it in drive so it can go a different direction and change in  velocity. You can also just turn around and go the other way or slow down.

      2.    a) Acceleration: The rate at which an object changes its velocity.

           b) Deceleration: Acceleration that is opposite to the direction of motion.

      3.   It occurs when the speed of an object changes, or it’s direction of motion changes, or both. Changes in velocity can be either positive or negative. To find the velocity you have to subtract the initial by the final velocity.

      4.   Velocity = (+ 20 m/s) – (+ 0 m/s) =  + 20 m/s

      5.   They both can be the same if two objects or something goes at the same speed, but if the acceleration is greater the velocity can change faster than something have a lower acceleration.

     6.   a) Negative

           b) Zero

           c) Positive

           d) Positive

           e) Negative

     7.  a) (+ 8 m/s) – (+ 0 m/s) = + 8 m/s

          b) (+ 12 m/s) – (+ 8 m/s) = + 4 m/s

          c) (+ 12 m/s) – (+ 12 m/s) = 0 m/s

         d) (+ 15 m/s) – (+ 12 m/s) = + 3 m/s

         e) (- 9 m/s) – (+ 15 m/s) = - 24 m/s

    8. a) The speed of an object increases.

        b) The speed of an object decreases.

   9. a) (+ 25 m/s) – (- 4 m/s) = - 29 m/s

       b) The direction of the cars acceleration is negative or backwards the opposite of the direction it was travelling at the start.

10. a) He is moving forward so he has a positive acceleration, since he started at home plate and made it back there by running at a constant speed moving forward in a circle.

      b) The car is moving forward so it is positive, since it just started the race.

         

9-1B Change in Velocity Activity

What to Do

1.

Time (s)	0	20	40	60	80	100
Velocity (m/s [forward])	11	16	18	18	14	11

2. (a) (+ 16 m/s) - (+ 11 m/s) = + 5 m/s

    (b) (+ 18 m/s) – (+ 16 m/s) = + 2 m/s

    (c) (- 18 m/s) – (+ 18 m/s) = 0 m/s

    (d) (- 14 m/s) – (+ 18 m/s) = - 32 m/s

    (e) (- 11 m/s) – (+ 14 m/s) = - 25 m/s

What Did You Find Out?

1. 0 s to 40s it was speeding up since it had a positive acceleration.

2. 60 s to 100s it was slowing down, because it had a negative acceleration.

3. 40 to 60s the velocity was zero, because each time intervals had the same velocity. 

8.1 Motion Check Your Understanding Questions #All

1. Scalar Quantity: Is a quantity that describe magnitude, but do not include direction are called scalar quantities or scalars.

2. Vector Quantity: A vector quantity includes both a magnitude and a direction.

3. Magnitude refers to the size of measurement or the amount of the number you are counting.

4. Position is and actual position that someone may be in at the time, while distance is how far something or someone has traveled.

5.

(a) Distance=Scalar

(b) Time intervals=Scalar

(c) Position=Vector

(d) Displacement=Vector

7. The mathematical difference is time interval.

8. Delta

9. Displacement describes the straight point distance and direction from one place to another.

10. Velocity * Time

11. The object would have traveled 4m because it was uniform which means the object would have stayed the same constant speed all the way.

12.

(a) The Position


(b) The Time

13. A straight one on a 45^o angle.

14.

(a) 6m North

(b) 7m East

(c) 6m South

15.

(a) 6m east


(b) 6m east


(c) 6m west


(d) 0m

16. 12 m the object traveled in 10 s.

17. Unless it travels in a straight line.

8-1D Analyzing a Positive Time Graph Activity

8-1C Graphing Motion Data Activity

8-1B Distance and Displacement Activity

What to Do

1.

Time (s)	Position (m)
0	5m [E]
5	20m [W]
10	10m [W]
15	10m [E]
20	0m [E]

2.

Time Interval (s)	Distance Travelled (m)	Displacement (m)
0 s-5 s	15 m	15 m [E]
0 s-10 s	5m	5 m [E]
0 s-15 s	15 m	15 m [W]
0 s-20 s	5 m	5 m [E]

What Did You Find Out?

1.    (a) Yes

(b) It is because he never ended up in the same spot where he started when he travelled a certain distance.

2. When something or someone starts at a certain place and does not end up in the same place at the end of the walk or run.