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1. A student drives 40 km south in an attempt to get to a science fair competition before realizing he missed the exit. He turns

around and drives back north 15 km before arriving. The total time of travel was 0.75 hr. What is his speed? What is his
velocity?

2. A bus leaves Houston at 6:00 am headed toward Austin at a constant speed of 54.3 miles/hour. If Austin is located 190 miles west of Houston, approximately when will the bus arrive in Austin?

3. A girl rides her moped 5 km east and then turns around and rides 2 km west. The entire trip takes fifteen minutes. What are
her average speed and velocity?

User Inluxc
by
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1 Answer

3 votes

Answer:

1) = approximately 74 km/hr
2) = 9:30 AM
3) Avg speed = 28 km/hr
vel = 0.

Step-by-step explanation:

Here is how you do it:

1) To find the student's speed, we can use the formula:

Speed = Distance / Time

The student traveled a total distance of 40 km south and 15 km north, which gives a total distance of 40 km + 15 km = 55 km. The total time of travel was 0.75 hours.

Speed = 55 km / 0.75 hr ≈ 73.33 km/hr

Therefore, the student's speed is approximately 73.33 km/hr or 74 km/hr.

To calculate the student's velocity, we need to consider both magnitude and direction. Since the student ended up at the same position as the starting point, the displacement is zero. Therefore, the velocity is also zero.

2) The distance between Houston and Austin is 190 miles. The bus is traveling at a constant speed of 54.3 miles/hour. We can use the formula:

Time = Distance / Speed

Time = 190 miles / 54.3 miles/hour ≈ 3.50 hours

The bus will arrive in Austin approximately 3.50 hours after leaving Houston.

If the bus leaves Houston at 6:00 am, it will arrive in Austin around 9:30 am.

3) The girl rode 5 km east and then turned around and rode 2 km west. The total distance traveled is 5 km + 2 km = 7 km. The entire trip took fifteen minutes, which is equal to 15/60 = 0.25 hours.

Average Speed = Total Distance / Total Time

Average Speed = 7 km / 0.25 hr = 28 km/hr

Therefore, the girl's average speed is 28 km/hr.

To calculate the girl's velocity, we need to consider both magnitude and direction. The girl's initial direction was east, and her final direction was west. Since the starting and ending points are the same, the displacement is zero. Therefore, the velocity is also zero.

User Nitanshu
by
8.8k points