To find the average velocity of Holden's race car, we use the formula for average velocity:
\[ \text{Average Velocity} = \frac{\text{Displacement}}{\text{Time}} \]
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Calculate the displacement:
- Holden first travels 20 meters east and then turns around to travel 40 meters west.
- Displacement is the final position relative to the starting position.
- After traveling 20 meters east, he turns around and travels 40 meters west.
- His final position is \( -20 \) meters from the starting position (20 meters east is positive and 40 meters west is negative).
- Thus, the displacement is:
\[ \text{Displacement} = -20 , \text{meters} \]
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Calculate the time:
- The total time taken for the journey is 5 seconds.
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Calculate average velocity:
- Now we can calculate the average velocity:
\[ \text{Average Velocity} = \frac{-20 , \text{meters}}{5 , \text{seconds}} = -4 , \text{m/s} \]
The negative sign indicates that the direction of average velocity is west.
Thus, the average velocity of the race car is 4 m/s west.