would you say these are fair physics questions?

[blackmi4]

Does anyone see a problem with the book offering the following answers as correct to the questions?

1. Question
Which of the following gives the average velocity of an athlete running on a circular track with a circumference of 1/2km, if that athlete runs 1km in 4 minutes?

1. Answer
0 m/s is correct since the runner is on a circular track of ? km, the runner will end up where he/she began. This is zero displacement and zero velocity.

2. Question
The earth moves around the sun at approximately 30 m/s. Is the earth accelerating?

2. Answer
Yes, because the velocity is not constant.. Acceleration is the rate of change of velocity. Since velocity is a vector it specifies direction. The direction of the earth's motion is constantly changing.

I feel like number 2 should be No, because the net displacement is 0 using the logic from the answer in number 1.

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[mcloaf]

These questions and answers are totally legit. Basics of speed, velocity, and acceleration.

 

[sps27]

Does anyone see a problem with the book offering the following answers as correct to the questions?

1. Question
Which of the following gives the average velocity of an athlete running on a circular track with a circumference of 1/2km, if that athlete runs 1km in 4 minutes?

1. Answer
0 m/s is correct since the runner is on a circular track of ? km, the runner will end up where he/she began. This is zero displacement and zero velocity.

2. Question
The earth moves around the sun at approximately 30 m/s. Is the earth accelerating?

2. Answer
Yes, because the velocity is not constant.. Acceleration is the rate of change of velocity. Since velocity is a vector it specifies direction. The direction of the earth's motion is constantly changing.

I feel like number 2 should be No, because the net displacement is 0 using the logic from the answer in number 1.

Question 1 is slightly ambigous. It talks velocity but does not specify which, angular or translational. I think they just want you to differentiate displacement v/s distance in that one. Similarly Question 2, well one can always say there is centripetal acceleration so yes, it is accelerating. Besides earth orbit around sun is not a perfect circle........but i agree....the questions do seem a little tardy.......let is slide and move on i'd say....

It is often the case I've noticed that one has to gauge the mindset of the question maker as to what he /she is hinting at with a particular question.....