Question

level 5 q1 a ball is rolled at a speed of 12 m/s. after 36 seconds, it comes to a stop. what is the acceleration of the ball? a. -3 m/s² b. 3 m/s² c. 0.33 m/s² d. -0.33 m/s² level 5 q2 a parachute slows a skydiver from 85 m/s to 45 m/s in 4.5 seconds? what is the acceleration of the parachute? a. 8.9 m/s² b. -8.9 m/s² c. 0.1 m/s² d. -0.1 m/s² level 5 q3 a plane taking off from the runway. this is an example of a. speed b. velocity c. acceleration d. all of the above level 5 q4 the fastest pitch ever thrown was 169.14 kph (105.1 mph). this is an example of a. speed b. velocity c. acceleration d. none of the above

Explanation:

Q1

Step1: Recall the acceleration formula

The formula for acceleration is \(a=\frac{v - u}{t}\), where \(v\) is the final velocity, \(u\) is the initial velocity, and \(t\) is the time.

Step2: Identify the values

Given \(u = 12\ m/s\), \(v=0\ m/s\) (comes to a stop), and \(t = 36\ s\).

Step3: Substitute into the formula

\(a=\frac{0 - 12}{36}=\frac{- 12}{36}=-0.33\ m/s^{2}\)

Q2

Step1: Use the acceleration formula

\(a=\frac{v - u}{t}\), with \(u = 85\ m/s\), \(v = 45\ m/s\), and \(t=4.5\ s\)

Step2: Substitute values

\(a=\frac{45 - 85}{4.5}=\frac{-40}{4.5}\approx - 8.9\ m/s^{2}\)

Q3

Step1: Understand the concepts

Acceleration is a change in velocity. When a plane takes off, its velocity is changing (increasing), so it is an example of acceleration.

Q4

Step1: Define speed and velocity

Speed is a scalar quantity (magnitude only), while velocity is a vector (magnitude and direction). The fastest pitch is given as a magnitude (\(169.14\ kph\)), so it is an example of speed.

Answer:

Q1: D. \(-0.33\ m/s^{2}\)
Q2: B. \(-8.9\ m/s^{2}\)
Q3: C. Acceleration
Q4: A. Speed