What is the Average Speed of a Car on a 100 Minute Trip?

In summary, a car travels at three different speeds for a total of 100 minutes. The average speed for the trip can be calculated by dividing the total displacement by the total time. However, in order to solve this question, a specific value for v is needed. The given answer of 33.33 may represent the average time per journey of the car, but more information is needed to determine the units and solve for the average speed.
  • #1
cmkc109
103
0

Homework Statement



A car travels at a speed v (km/h) for 40 minutes, then at a speed v/2 for 40 minutes, and finally at a speed v/3 for 20 minutes. What is the average speed for the trip

Homework Equations



avg v = displacement / time

The Attempt at a Solution



40v + 20v + 20/3 v = displacement
time = 40+ 40+ 20 = 100minutes

The answer given is 33.33
but, how do you cancel out the v.. I'm confused :(
 
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  • #2
the average velocity is (5/9)*v
 
  • #3
what are the units of the 33.33
 
  • #4
i don't remember :/ but in general, how to solve this question?
 
  • #5
you can't eliminate the v unless it gives you a value for it. the only thing i can think of is that 33.33 is the average time per journey of the car. if it is asking for the average speed then v must have been 60 km/h.
 

1. What is average velocity?

Average velocity is the measure of an object's overall displacement over a specific period of time. It is calculated by dividing the total displacement by the total time taken.

2. How do you find average velocity?

To find average velocity, you need to calculate the total displacement of the object and the total time taken. Then, divide the displacement by the time taken to get the average velocity.

3. What is the formula for average velocity?

The formula for average velocity is average velocity = total displacement / total time taken. This can also be represented as v = Δx / Δt, where v is average velocity, Δx is displacement, and Δt is time taken.

4. What are the units for average velocity?

The units for average velocity are typically distance over time, such as meters per second (m/s) or kilometers per hour (km/h). However, the specific units may vary depending on the context of the problem.

5. How is average velocity different from instantaneous velocity?

Average velocity is the overall measure of an object's displacement over a period of time, while instantaneous velocity is the velocity of an object at a specific moment in time. Average velocity takes into account the total distance traveled, while instantaneous velocity only considers the velocity at a single point in time.

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