Question

1. an object travels 19 m/s for 25 s and then at 20.0 m/s for 15 s. what is the average speed?

Explanation:

Step1: Identify the speeds and times

The object has two speeds: \( v_1 = 19\space m/s \) for \( t_1 = 26\space s \), and \( v_2 = 20.0\space m/s \) for \( t_2 = 15\space s \).

Step2: Calculate the total distance

The distance formula is \( d = v \times t \). For the first part, \( d_1 = v_1 \times t_1 = 19 \times 26 \). For the second part, \( d_2 = v_2 \times t_2 = 20.0 \times 15 \). Then total distance \( D = d_1 + d_2 \).
\( d_1 = 19\times26 = 494\space m \)
\( d_2 = 20.0\times15 = 300\space m \)
\( D = 494 + 300 = 794\space m \)

Step3: Calculate the total time

Total time \( T = t_1 + t_2 = 26 + 15 = 41\space s \)

Step4: Calculate the average speed

Average speed \( v_{avg} = \frac{D}{T} = \frac{794}{41} \approx 19.37\space m/s \)

Answer:

The average speed is approximately \( 19.4\space m/s \) (or more precisely \( \approx 19.37\space m/s \))