karen is running forward at a speed of 9 m/s. she tosses her sweaty head - band backward at a speed of 20…
karen is running forward at a speed of 9 m/s. she tosses her sweaty head - band backward at a speed of 20 m/s. the speed of the head - band, to the nearest whole number relative to a stationary observer watching karen, is m/s.
Answer
Explanation:
Step1: Define the positive - direction
Let the forward direction (Karen's running direction) be positive. Karen's velocity $v_{K}=9\ m/s$. The velocity of the head - band relative to Karen $v_{HB - K}=- 20\ m/s$ (negative because it is thrown backward).
Step2: Use the relative - velocity formula
The formula for relative velocity is $v_{HB}=v_{HB - K}+v_{K}$, where $v_{HB}$ is the velocity of the head - band relative to the stationary observer. Substitute the values: $v_{HB}=-20 + 9$.
Step3: Calculate the result
$v_{HB}=-11\ m/s$. The magnitude of the velocity (speed) is $11\ m/s$.
Answer:
11