a girl walks 1km north in 15min.then walks 200m south west in 60sec.what is her average velocity?
Displacement = 1000i +1000i + 200[225o] = 1000i + 200*Cos225 + 200*sin225 =
1000i - 141.4 - 141.4i = -141.4 + 858.6i
= 870m[99.4o]CCW = 80.6o N. of W.
V = D/t = 870m[99.4o]/960s = 0.91 m/s.
assignmet
To find the average velocity of the girl, we need to determine both the total displacement and the total time taken.
First, let's break down the movements:
1. The girl walks 1 km north in 15 minutes.
2. Then, she walks 200 m southwest in 60 seconds.
To calculate the average velocity, we need to convert both displacement values to a common unit. Let's convert the distance of 200 m southwest to kilometers.
Converting 200 meters to kilometers:
200 meters = 200/1000 = 0.2 kilometers
Therefore, the girl walked 0.2 kilometers southwest in 60 seconds.
Now, let's calculate the total displacement.
For the 1 km northward movement, the displacement is +1 km (positive, as it is north).
For the 0.2 km southwest movement, the displacement is -0.2 km (negative, as it is southwest).
So, the total displacement is 1 km - 0.2 km = 0.8 km (to the north).
Next, we calculate the total time taken:
The girl took 15 minutes for the northward movement and 60 seconds for the southwest movement. To calculate the total time taken, we need to convert the time for the southwest movement to minutes.
Converting 60 seconds to minutes:
60 seconds = 60/60 = 1 minute
Therefore, the girl took 15 minutes + 1 minute = 16 minutes.
Now that we have both the total displacement and the total time taken, we can calculate the average velocity using the formula:
Average velocity = Total displacement / Total time taken
Average velocity = 0.8 km / 16 minutes
Calculating the average velocity:
Average velocity = 0.8 km / 16 minutes
Average velocity = 0.05 km/min
Therefore, the girl's average velocity is 0.05 kilometers per minute, in the north direction.