Speed-time graphs
A sloping line on a speed-time graph represents an acceleration . The sloping line shows that the speed of the object is changing. The object is either speeding up or slowing down.
If the line slopes upward from left to right
, this means the object is speeding up.
How do you know if a graph is speeding up?
- If v is in positive quadrant, object is speeding up.
- If v is in negative quadrant, object is slowing down.
How do you know if a particle is speeding up or slowing down?
If velocity and acceleration have the same sign, the particle is “speeding up.” If
velocity and acceleration have opposite signs
, the particle is “slowing down.”
How do you find the speed of a particle increasing?
Speed increases when velocity and acceleration are positive
. Speed decreases when velocity increases/decreases and acceleration does the opposite of velocity. The particle P reverses (changes) direction when v=0 and a≠0. A particle moves along a line according to s=2t3 9t2 + 12t 4 where t≥0.
How can you determine if an object is speeding up or slowing down from the position velocity and acceleration time graphs?
- If v is in positive quadrant, object is speeding up.
- If v is in negative quadrant, object is slowing down.
How do you know when a particle is moving left?
The particle is considered moving to the right when the velocity function is positive (above the x-axis). The particle is considered moving to the left when
the velocity function is negative
(below the x-axis).
What does constant speed look like on a graph?
A constant velocity means the position graph has a constant slope (of 11.11 m/s). It’s a
straight line sloping up
, and starting below the origin.
Is speed the same as velocity?
Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object’s movement. Put another way, speed is a
scalar value
, while velocity is a vector. … In its simplest form, average velocity is calculated by dividing change in position (Δr) by change in time (Δt).
Is slope the same as acceleration?
It was learned earlier in Lesson 4 that
the slope of the line on a velocity versus time graph is equal to the acceleration of the object
. If the object is moving with an acceleration of +4 m/s/s (i.e., changing its velocity by 4 m/s per second), then the slope of the line will be +4 m/s/s.
How can you tell if an object is slowing down on a graph?
That is, if the line is getting further away from the x-axis (the 0-velocity point), then the object is speeding up. And conversely,
if the line is approaching the x-axis
, then the object is slowing down.
What is an acceleration vs time graph?
An acceleration vs. time graph plots
acceleration values on the y-axis, and time values on the x-axis
. … time graph, the slope at that point (derivative) will always be equal to the acceleration at that time. So, if at some moment your acceleration is positive, then at that moment your velocity will be increasing.
Can an object have a speed of zero while it has an acceleration that is not zero?
It is
possible to have a non-zero value of acceleration
when the velocity of a body is zero. … At the highest point, the velocity of the ball becomes zero, after which it starts to fall down. At this point, the velocity of the ball is zero yet its acceleration is equal to g=9.8m/s2.
At what time t does the direction of motion of the particle change from right to left?
Thus the particle changes directions exactly once at
t=3 seconds
. The acceleration is the first derivative of the velocity. Hence, to get the velocity from the acceleration requires integration in time.
Can the speed of a particle increases as its acceleration decreases?
Yes,
speed can increase even if the acceleration decreases
. Acceleration is the rate of change of velocity.
