Physics
posted by Miaow .
Could someone please review my answers and tell me if I am on the right track? Thank you!
A student drove to the university from her home and noted that the odometer reading of her car increased by 12.0 km. The trip took 18.0 min. (a) What was her average speed? (b) If the straightline distance from her home to the university is 10.3 km in a direction 25.0o south of
east, what was her average velocity? (c) If she returned home by the same path 7 h 30 min after she left, what were her average speed and velocity for the entire trip?
a.) average speed: 12 km/18 min=0.67 km/min
b.) average velocity: (must find time first)
t: 10.3 km/ 0.67 km = 15.4 min
average velocity: 10.3 km/15.4 min = 0.67 km/min
c.) average speed: 24 km/450 min = 0.05 km/min
average velocity: 0 km/450 min = 0

(a) we usually express car speeds in km/hour
(b) Displacement = 10.3 km in direction 25° S of east
Time = 18 min = 0.3 hour
So velocity = 34.3 km/hr in direction 25° S of E.
(c)Correct. 
Thank you very much!
I wondered if I should switch to km/hr. And, I was SURE I was wrong on B but AMAZED I was right on C. :) 
You're welcome!
Yes, velocity is a vector, so it is described by the magnitude (speed) and direction.
The same goes for displacement, which is also a vector, and therefore is described by the magnitude and direction.
Keep up the good work! 
so i got all answers but part c for average velocity is zero since there is no info about the displacement?

For part c, you put average speed as 0.05 km/min, which is correct.
Subsequently, as part 2 of (c), you did put average velocity as 0.
Perhaps there was a confusion of the questions. 
I am confused on how you got the 24km in part c. Could someone please explain that?
Respond to this Question
Similar Questions

physics, please help check
A rocket car is traveling on a linear horizontal frictionless track when it suddenly runs out of fuel. The car has achieved a speed of 100 meters per second at the very moment the fuel is completely spent. The track then suddenly changes … 
Physics
An odometer in a car has a reading of 50 km at the beginning of a trip and a reading of 125 km half an hour later. What is the average speed of the car? 
PHYSICS
An odometer in a car has a reading of 50 km at the beginning of a trip and a reading of 125 km half an hour later. What is the average speed of the car? 
math
The odometer in your mother's car reads 2056 miles less than the odometer in your uncle's car. Your mother's odometer reads 22010 miles. About how many miles are on the odometer of your uncle's car? 
prealgerbra
I have been working on this problem for an hour and a half! I keep getting 1.33 but I know that's not right!! Jim drove the 120 miles to grandmothers house in 3 hours. He increased the speed by 10 miles per hour on the way home. How … 
Discrete Math
(2) Suppose A is the set of students currently registered at the University of Calgary, B is the set of professors at the University of Calgary, and C is the set of courses currently being offered at the University of Calgary. Under … 
Physics
A disgruntled physics student sees the front end of his teacher's car below him at the base of a building. If the student is 5.0 m high above the car which is 3.0 m long and traveling only 3m/s to the right, will the apple of the student … 
Physics
A disgruntled physics student sees the front end of his teacher's car below him at the base of a building. If the student is 5.0 m high above the car which is 3.0 m long and traveling only 3m/s to the right, will the apple of the student … 
Math
On their vacation, the Li family traveled from their home to a resort in the mountains. The odometer in their car read 35286.9 miles when they started and 35514.2 miles when they returned home. What was the distance from their home … 
Math
The odometer on a car shows 26962 km. Notice that this number is a palindrome. After the car has travelled two hours at a constant rate, the odometer shows the next possible palindromic number. How fast is the car travelling?