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What does a v-t graph look like? Time is marked on the horizontal axis and velocity is on the vertical. Graphs that represent an object’s velocity versus its time.
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Velocity-Time Graphsand Acceleration
What does a v-t graph look like?
• Time is marked on the horizontal axis and velocity is on the vertical.
• Graphs that represent an object’s velocity versus its time.
What can we determine from a velocity time graph?
• Velocity and speed• Time• Acceleration• Displacement and distance
What can we determine from a velocity time graph?
• Velocity - reading directly off the y-axisa) v(1.0) =
b) v(5.0) =
c) V(11.0) =
What can we determine from a velocity time graph?
• Time (read off the x-axis) a) Time when v = 50
b) Time when v = - 40
a) Time when v = 0
What can you find from a v-t graph
• Instantaneous Acceleration = slope at a point on the graph (you may have to use a tangent)
• Average acceleration = finding the slope of a segment (use the start and end points)
What can we determine from a velocity time graph?
• Acceleration = v/t = slope a) a(3.0)
b) a (4.0)
c) a (12.0)
d) a (ave for first 11.0 s)
What can we determine from a velocity time graph?
• Displacement = area under the curve• NOTE: Area formulas:
– Arearectangle = length x width
– Areatriangle = ½ base x height
a) d (first 1.0s)
b) d (first 4.0 s)
c) a (entire trip)
Velocity-Time Graphs
Interpreting v-t graphs
• Horizontal lines show uniform motion (constant speed and direction).
• Inclined lines show change in speed or direction, or both: in other words accelerated motion.
Summary Slide: Velocity-Time Graphs
• Independent Variable =• Dependent Variable =• Above x-axis =
• Below x-axis =
• On x-axis =
• Linear sections
Summary Slide: Velocity-Time Graphs
• Slope =• + slope (2 scenarios)=
• - slope (2 scenarios) =
• Horizontal Line
• Average acceleration:
• Instantaneous acceleration:
Summary Slide: Velocity-Time Graphs
• Steeper slope means _______________________
• To find velocity: read off ______ at a point
• To find displacement:
• Find time: read off the ------------------- at a point
Summary Slide: Velocity-Time Graphs
• Independent Variable = time• Dependent Variable = velocity• Above x-axis = moving forward (positive v)
• Below x-axis = moving backward (negative v)
• On x-axis = stationary (v = 0)
• Linear sections = constant acceleration
Summary Slide: Velocity-Time Graphs
• Slope = acceleration• + slope (2 scenarios)= moving forward, speeding up OR moving backward, slowing down
• - slope (2 scenarios) = moving forward, slowing downOR moving backward, speeding up
• Horizontal Line = no acceleration (slope = 0)
• Average acceleration: draw a line from start to end and find its slope
• Instantaneous acceleration: slope at a point (use tangent)
Summary Slide: Velocity-Time Graphs
• Steeper slope means speeding up or slowing down quickly (changing speed quickly – like hitting the brakes rather than putting the brakes on 10m before stop sign)
• To find velocity: read off y-axis at a point
• To find displacement: area between curve and x-axis (find total area of rectangles and triangles)
• Find time: read off the x-axis at a point