objectives: analyze and explain velocity vs. time graphs.\nvocabulary: acceleration\npractice:\n10. list the…
objectives: analyze and explain velocity vs. time graphs.\nvocabulary: acceleration\npractice:\n10. list the different ways an object can accelerate.\n11. analyze the motion of an object that has an acceleration of 0 m/s²\n12. by the time an airplane reaches the end of a runway, it has reached a speed of 80 m/s in 20 s. what is its acceleration?\n13. a puppy is running with a speed of 11.2 m/s towards its owner when it gets distracted by a squirrel and stops running. if it halted its run in 2 s, what was the acceleration of the puppy?\n14. explain what the slopes on a distance vs. time graph and on a velocity vs. time graph tell you.\n15. a ball is dropped from a cliff and has an acceleration of 9.8 m/s². how long will it take the ball to reach a speed of 24.5 m/s?\n16. indicate what kind of acceleration is shown in the following graphs.
Answer
Explanation:
Step1: Recall acceleration formula
The formula for acceleration is $a=\frac{v - u}{t}$, where $v$ is final - velocity, $u$ is initial - velocity, and $t$ is time. The airplane starts from rest, so $u = 0\ m/s$, $v=80\ m/s$, and $t = 20\ s$.
Step2: Substitute values into formula
$a=\frac{80 - 0}{20}$ $a = 4\ m/s^{2}$
Answer:
$4\ m/s^{2}$
Explanation:
Step1: Identify initial and final velocities and time
The puppy's initial velocity $u = 11.2\ m/s$, final velocity $v = 0\ m/s$ (it stops), and time $t = 2\ s$.
Step2: Use acceleration formula
$a=\frac{v - u}{t}=\frac{0 - 11.2}{2}$ $a=- 5.6\ m/s^{2}$
Answer:
$-5.6\ m/s^{2}$
Brief Explanations:
On a distance - vs - time graph, the slope represents the speed of the object. A steeper slope means a higher speed. On a velocity - vs - time graph, the slope represents the acceleration of the object. A positive slope means positive acceleration, a negative slope means negative acceleration (deceleration), and a zero slope means zero acceleration (constant velocity).
Answer:
On a distance - vs - time graph, slope represents speed. On a velocity - vs - time graph, slope represents acceleration.
Explanation:
Step1: Use acceleration formula to find time
We know $a=\frac{v - u}{t}$, and the ball is dropped from rest so $u = 0\ m/s$, $a = 9.8\ m/s^{2}$, $v = 24.5\ m/s$. Rearranging the formula for $t$ gives $t=\frac{v - u}{a}$.
Step2: Substitute values
$t=\frac{24.5-0}{9.8}$ $t = 2.5\ s$
Answer:
$2.5\ s$
Brief Explanations:
The first graph has a positive - sloped straight line, so it represents positive acceleration (the velocity is increasing with time). The second graph has a negative - sloped straight line, so it represents negative acceleration (deceleration, the velocity is decreasing with time). The third graph has a horizontal line, so it represents zero acceleration (constant velocity).
Answer:
First graph: positive acceleration. Second graph: negative acceleration. Third graph: zero acceleration.