Distance & Displacement
Length of the total path traveled by an object.
Distance
What are the SI (standard) units for speed?
m/s
Velocity describes both _________ and __________ of an object.
Speed and Direction
What are the SI (standard) units for acceleration?
m/s2
Which reference point would help passengers on a train determine how fast they are traveling?
a) the person sitting next to them
b) trees out the window
c) attendant walking down the train aisle
b) trees out the window
_____________ is the direction from the start point and length of a line connecting start to end points.
Displacement
What is the formula for calculating speed?
Speed = Distance / Time
S = D/T
How do we find the resultant velocity if both velocities are moving in the same directions?
Add them
What is the formula for acceleration?
Object is at rest/not moving.
When will an object's displacement be equal to 0?
When start and end points are the same.
What is the speed of a person that runs 250 m in 12.5 seconds?
20 m/s
Describe how two objects could have the same speed but different velocities?
The objects are moving in different directions
What does it mean if an object's acceleration is negative?
the object is slowing down (decelerating)
What type of speed does a car's speedometer measure?
Instantaneous Speed
An object traveled 15 m east, turned around and went back 20 m west.
What is the object's distance AND displacement?
distance = 35 m
displacement = 5 m West
How long will it take a plane traveling 550 km/h to fly 1375 km?
t = d /s
t = 1375 km / 550 km/h
t = 2.5 hours
A sailboat is in the ocean. The wind is blowing to the east 5 m/s while ocean currents are also moving east 13 m/s.
What is the resultant velocity of the boat?
18 m/s east.
What does it mean if an object in motion has an acceleration equaling zero (0).
There is not change in speed / object traveling at constant speed.
What does the slope represent on a distance-time graph?
Speed
Adam had to go to the store. He walked 28 m north, realized he passed it and walked back south 3 m.
What was Adam's distance AND displacement
Distance = 31 m
Displacement = 25 m North
John walks to his friend's house. He walks 50m in 25 seconds, stops for 5 seconds, and then runs the last 40m in 15 seconds. What is John’s average speed of the trip to his friend's?
= (50 m + 40 m) / (25 s + 5 s + 15 s)
= 90m / 45 s = 2 m/s
A person is on a moving walkway at the airport. One problem.... they entered the walkway going in the opposite direction. The walkway is moving 3 m/s east while the person walks 5 m/s west.
What is the person's resultant velocity?
2 m/s west
A person is walking 4 m/s and 5 seconds later runs at a speed of 11 m/s.
What is the person's acceleration?
3 m/s2
What does it mean if a measurement is a vector?