Question

level 2 q1 a sailboat moves faster as the wind picks up speed. this is an example of a. speed b. velocity c. acceleration d. all of the above level 2 q2 a race car accelerated from rest to 60 m/s when it crossed the finish line 8 seconds later. what was the cars acceleration? a. 0.13 m/s² b. 7.5 m/s² c. 52 m/s² d. 68 m/s² level 2 q3 light travels at 300,000,000 m/s. this is an example of a. speed b. velocity c. acceleration d. speed and acceleration level 2 q4 by plane, a trip to disney world took 10 hours over a distance of 816 km. what is the average speed of the plane? a. 8,160 km/h² b. 8,160 km/h c. 81.6 km/s² d. 81.6 km/h

Explanation:

Q1

Acceleration is the rate of change of velocity. When the sailboat picks up speed (changes its velocity), it is accelerating. Speed is just the magnitude of how fast it's moving, and velocity is speed with direction. But the key here is the change in speed (a change in velocity), which is acceleration.

Q2

Step1: Recall the acceleration formula

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

Step2: Identify the values

Given \(u = 0\ m/s\) (starts from rest), \(v=60\ m/s\), and \(t = 8\ s\).

Step3: Substitute into the formula

\(a=\frac{60 - 0}{8}=\frac{60}{8}=7.5\ m/s^{2}\)

Q3

Speed is a scalar quantity (just magnitude). When we say light travels at \(300,000,000\ m/s\), we are only giving the magnitude of how fast light is moving. Velocity would require a direction (which isn't given here), and acceleration is a change in velocity (no change is indicated here).

Q4

Step1: Recall the average - speed formula

The formula for average speed \(v=\frac{d}{t}\), where \(d\) is distance and \(t\) is time.

Step2: Identify the values

Given \(d = 816\ km\) and \(t=10\ h\)

Step3: Substitute into the formula

\(v=\frac{816}{10}=81.6\ km/h\). Also, check the units: \(km/h^{2}\) (option A) and \(km/s^{2}\) (option C) are units of acceleration (since acceleration has units of \(\frac{distance}{time^{2}}\)), and \(8160\ km/h\) (option B) is incorrect calculation (\(\frac{816}{10}
eq8160\)).

Answer:

Q1: C. Acceleration
Q2: B. 7.5 m/s²
Q3: A. Speed
Q4: D. 81.6 km/h