Distance and Displacement
What are the SI units for distance and displacement?
Meters (m)
What are the SI units for speed and velocity?
Meters per Second (m/s)
What is the SI unit for acceleration?
Meters per Second per Second (m/s2)
A "moving sidewalk" at the airport moves forward at 1.5 m/s. If a person stands still on it, what is their resultant velocity?
1.5 m/s forward
What is the SI unit for time?
Seconds
What is the difference between scalars and vectors?
Vectors include a direction and scalars do not
A mosquito flies 3m in 20 seconds. What is the mosquito's speed?
0.15 m/s
What are the 3 different ways that an object can accelerate?
Speed up, slow down, and/or change direction
An escalator moves up at a speed of 1 m/s. If you walk up the escalator with a walking speed of 0.8 m/s, what is your resultant velocity?
1.8 m/s up
Out of the metric prefixes that we talked about this year, which one is the largest?
Kilo
A spider crawls 1.3 m up the side of a house, then crawls 0.2 m back down.
What is the total distance traveled and what is the displacement?
Distance traveled is 1.5 m, displacement is 1.1 m up
An ant walks 1 meter north, and then 1.5 meters west. The trip takes 80 seconds (ant legs are short)
What is the ant's average speed?
About 0.03 m/s
A squirrel sitting in a tree at rest falls and speeds up to 19.6 m/s in 2 seconds. What is the acceleration of the falling squirrel?
9.8 m/ss (gravity always makes things fall with this amount of acceleration. Remember that, we will use it a lot next unit!)
Mike's river boat can sail 4 m/s on still water. If he sails it South at this velocity in a river that flows North at a 1.2 m/s, what will be his resultant velocity?
2.8 m/s South
Positive acceleration means the object is __________
Negative acceleration means the object is __________
Positive acceleration means the object is SPEEDING UP
Negative acceleration means the object is SLOWING DOWN
A tourist is lost in a city and is trying to find their hotel. They walk 1 city block West, then 3 city blocks North, then 1 city block east.
If each city block is 300m, what is the total distance traveled and what is their displacement? Answer in meters.
Distance traveled is 1500m and displacement is 900m North
A patrolling security guard walks 100m East, then walks 40m West. This trip takes them 120 seconds.
What is the security guard's velocity? (you need to find displacement first)
0.5 m/s East
If an object has a positive acceleration of 2 m/s2 for 10 seconds, how does it's velocity change?
It speeds up by 20 m/s
A car is driving East at 30 m/s. If the driver throws a piece of trash into the back seat at a speed of 2 m/s, what is the resultant velocity of the trash?
28 m/s East
Convert 1.35 kg into cg
135,000 cg
An elephant walks with a constant velocity of 0.2 m/s to the right for one minute. What is their displacement?
12 meters to the right (did you remember to change minutes into seconds?)
A hiker walks from their car up a mountain trail to reach a cliff with a beautiful view, then walks back down to their car. If we were to calculate the average speed and the average velocity for the whole hike, which would be greater? (or are they the same?)
Speed would be greater because the velocity would be 0 m/s (since the displacement is 0m)
A dog walks out into the street and a driver slams on their brakes to avoid hitting it. Their car goes from 40 m/s to 5 m/s in 3 seconds. What is the car's acceleration?
-11.67 m/s2 (it's negative because the car is slowing down)
Sue is running on a big treadmill that moves backwards at 1.9 m/s. She manages to outrun the treadmill and moves forward with a resultant velocity of 0.6 m/s. What is Sue's running velocity?
2.5 m/s forward
A horse trots around in its pasture for 6 minutes. It has an average speed of 5 m/s, but an average velocity of 0 m/s.
Explain how this can be true.
It ended up back where it started (velocity is only 0 if the displacement is 0)