Finding the average velocity of a car traveling at different speeds and angles

In summary, the car traveled a total distance of 170.23 km in 3.3 hours, resulting in an average velocity of 51.59 km/h at an angle of 32.5 degrees north of east.
  • #1
Intrusionv2
31
0

Homework Statement



A car travels east at 95 km/h for 1.5 hours. It then travels 30.0° east of north at 111 km/h for 1.8 hours.

What is the average velocity for the trip? (Magnitude and degrees)

Homework Equations



law of cosines/resultant

The Attempt at a Solution



I have tried doing this:
d=952 + 1112 - 2(85*111)cos60 = 110km
v=110km / 3.3 hr = 33.1 m/s

for the angle...
tanx = Bsinx/ a + bcosx = 111sin60/95+111cos60 = 0.638
x = 32.5 north of east

Both of these were wrong...any help please??
 
Last edited:
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  • #2
Intrusionv2 said:
d=852 + 1112 - 2(85*111)cos60 = 170.23km
You have basically the right idea to use the law of cosines, but this step is wrong. If you include the units in the calculation, you will see why.
 
  • #3
diazona said:
You have basically the right idea to use the law of cosines, but this step is wrong. If you include the units in the calculation, you will see why.

Nvm, I see now.
 
Last edited:

1. What is average velocity?

Average velocity is a measure of the displacement of an object over a certain period of time. It is calculated by dividing the total displacement by the total time.

2. How is average velocity different from average speed?

Average velocity takes into account the direction of motion, while average speed only measures the magnitude of the movement. Average velocity is a vector quantity, while average speed is a scalar quantity.

3. How do you calculate average velocity?

To calculate average velocity, you divide the total displacement by the total time. The formula is: average velocity = (final position - initial position) / time.

4. Can average velocity be negative?

Yes, average velocity can be negative. This indicates that the object is moving in the opposite direction of the chosen positive direction. For example, if a car moves backwards, its average velocity would be negative.

5. What is the unit of measurement for average velocity?

The unit of measurement for average velocity is distance over time, such as meters per second (m/s) or kilometers per hour (km/h).

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