Physical Quantities
What is displacement? Give the definition and SI unit.
Change in position (m)
d=5 m, t=5 s. Find v.
v=1m/s
A rock is dropped off a 4.905m cliff. How long does it take to hit the ground?
1s
A rock is launched at 5m/s off a cliff. If it lands 10 m away, how long does it take to hit the ground?
2s
What does it mean for a velocity to be negative?
The object is moving in the "negative direction"
What is distance? Give the definition and SI unit.
The total length of a path m
vf=10m/s, vi=5m/s, t=2.5s. Find a.
a=2m/s2
A rock is launched horizontally at 10m/s off a 78.48m cliff. How far away does it land?
40m
A rock is launched horizontally at 10m/s off a cliff. If it lands 15m away, how high is the cliff?
11m
What does it mean for acceleration to be negative?
Either slowing down or speeding up, depending on sign of velocity.
What is velocity? Give the definition and SI unit.
The rate of change in displacement m/s
A car travels 8m forward, 8m back, and 2m forward. What is the total distance? What is the displacement?
Distance: 18m
Displacement: 2m
A rock is launched horizontally off a 78.48m cliff. If it lands 12m away, how fast was it initially going?
3m/s
A car flies off a cliff. Assuming its speed at the top of the cliff is 30m/s entirely in the x-direction, and it lands 90m away, How high was the cliff?
44m
Can a path's distance be shorter than its displacement?
No.
What is acceleration? Give the definition and SI unit.
The rate of change of velocity m/s2
A runner finishes a 100m race in 20s. What was their average speed during the race?
5m/s
A cannonball is launched at 10 m/s from a height of 25m at an angle of 15 degrees. How long does it take to hit the ground?
2.5 s
A cannon was fired. If it was released at an initial velocity of 15 m/s at an angle of 15 degrees from horizontal, and lands in 10 s, how far away does it land?
144.9 m
Consider two balls. One is dropped, and one is rolled off a table. If they both start at the same height, which will hit the ground first?
They land at the same time
How are velocity, acceleration, and displacement all related to each other?
Displacement is how far you travel, velocity is at what speed you travel, and acceleration is the rate that speed changes.
A car accelerates from rest to 10m/s in 2s. What is its acceleration?
5m/s2
A cannonball is launched at 10 m/s from a height of 20m at an angle of 30 degrees. How far away does it hit the ground?
22 m
A cannon was fired. If it was released at an initial velocity of 15 m/s at an angle of 15 degrees from horizontal, and lands in 10 m away, how high was it launched from?
5 m
How can you launch something from the same height with the same initial speed, but change the horizontal distance it travels?
Launch at an angle.