How do you find distance?
Add all the paths together
If a car travels 120 km in 2 hrs, what is its speed?
60 km/hr
What is the equation for acceleration?
A = Vf-Vi / t
When an object is speeding up on a motion dot diagram: Are the dots getting closer together, farther apart, remaining constant.
Getting farther apart
How can you tell if an object is moving in the negative direction on a velocity vs time graph?
When the graph is BELOW THE X-AXIS
If you walk 3 km east, and 4 km west, what is your distance traveled?
7 km
How is velocity different from speed?
Velocity must have a direction
A car increases its speed from 20 m/s to 40 m/s in 2 seconds. What is its acceleration?
Vf = 40 m/s, Vi = 20 m/s, t= 2 s
4+-20 / 2 = 20/2
= +10 m/s2
When an object is slowing on a motion dot diagram: Are the dots getting closer together, farther apart, remaining constant.
Closer together
Find the speed of an object using the following points pulled from a position vs time graph:
(10,5) and (12,0)
Units are m/s
Point 1: 10,5
Point 2: 12,0
y2-y1/x2-x1
0-5/12-10 = -5/2 = -2.5 m/s
If a runner completes a 400 m track, what is their displacement if they return to the starting point?
0 m
If a cyclist travels 60 km north in 3 hours, what is their velocity?
20 km/hr North
A car is traveling with a velocity of 56 m/s. After 5 seconds, the car comes to a stop. What is the acceleration of the car?
Vf = 0 m/s, Vi = 56 m/s, t= 5 s
0-56 / 5 = -56/5
= -11.2 m/s2
If an object is traveling in the negative direction. Which way do your arrows point? Right or left?
To the left
What does a flat line on a velocity vs time graph indicate about the object's motion?
The object is at a constant velocity!
A hiker walks 6 km east, and then 8 km west. What is their displacement?
2 km west
(45 m) / (12m/s) = 3.75 SECONDS
True/False
a car does not have an acceleration if it is making a right turn?
False
Acceleration happens when an object is SPEEDING UP, SLOWING DOWN, TURNING DIRECTIONS.
Draw a motion dot diagram for an object at rest
see motion dot diagram in google classroom
Draw a velocity vs time graph for the following description:
Joe is walking towards home with a constant velocity. He hears his mother call for him, so he speeds up.
See graph in google classroom
What is the difference between distance and displacement?
Distance: total length of the path traveled.
Displacement: the direct path from start to finish
D = s x t
70 x 9 = 630 m
What is the acceleration rule:
i.e.: speeding up = ___ direction
slowing down = ___ direction
speeding up = SAME direction (+V,+A or -V,-A)
slowing down = OPPOSITE direction (+V,-A or -V,+A)
Draw a motion dot diagram for an object that starts with a constant speed in the positive direction. After 3 seconds they come to a stop. 2 seconds later the object is speeding up in the negative direction
See motion dot diagram in google classroom.
Joe is running with a constant speed from his house. He ran 15 meters away and took a break to catch his breath. Then he runs home with a slower constant speed.
See graph posted in google classroom.