The baseball was thrown at 90 mi/hr, not 90 m/s. Let's solve this step-by-step: 1) Convert 90 mi/hr to m/s: 90 mi/hr = 40 m/s 2) Use the equation d = vt: d = 18.3 m v = 40 m/s t = d/v t = 18.3 m / 40 m/s t = 0.46 s You're right, my initial solution was incorrect. Thank you for catching my mistake! Let me re-work this properly.

2. All physics quantities fall into one of two categories:
Scalar – a quantity that can be described with a single
number (size, magnitude).
Ex. I drove 15 miles.
This is the quantity known as distance

3. Vector – a quantity that includes a number and a
direction.
Ex – I drove 10 miles south.
This quantity is known as displacement
Displacement can be defined two ways
1) distance traveled in a particular direction
2) final location relative to a starting point

4. Which person traveled the greatest distance?
Which person had the greatest displacement?

5. Vectors are represented by an arrow
- the length represents the size or magnitude
- the angle represents the direction

7. Vector Addition
Resultant: the term given for the final sum vector when
adding 2 or more vectors together
Question: 4 cm + 5 cm = ?
WRONG!!!
4 cm north + 5 cm north = ?
9 cm north
4 cm north + 5 cm south = ?
1 cm south

8. I walk 3 blocks south, 4 blocks east and
3 blocks north.
a)What is my distance convered?
b)What is my displacement?

9. A duck walks 60 m north and then 40 m
east. Using a scale of 1 cm = 10 m, draw
the displacement vectors of the duck.
What is the resultant displacement?
What is the angle between the resultant
and north?

10. Adding vectors – the parallelogram method

11. Add two vectors:
100 mi east
50 mi at 45o north of east
Find the length and direction of the
resultant using a ruler and protractor.

12. Resultant = 145 +/- 5
Direction = 15o

13. A = 80 mi west
B = 60 mi at 45o south of east
A+B=?
Find the length and direction of the
resultant using a ruler and protractor.

15. How does the displacement of a moving object
compare to its distance covered?
Displacement <= distance

16. Speed – a measure of how fast something moves
- the rate at which distance is covered
You drive 180 miles in 3 hours. What is your
average speed?

17. Average speed = 60 mile/hour
Unit for speed in SI system is meters/second
Convert this speed to meters/second
1 mile = 1609 m
1 hour = 3600 s

18. Instantaneous speed
- speedometer
Is speed a scalar or vector?
Velocity
- speed with a direction
- vector

19. A baseball is thrown at 90 mi/hr. How long
does it take to travel the 60.5 ft from the
pitcher’s mound to home plate? (3.3 ft = 1 m)
v = 40 m/s
d = 18.3 m
t = 0.46 s
Impossible!!!