I stand on an ideal skateboard (there is no friction with the floor) and start from rest when I push on a wall with a known force, I measure my speed after one second. Which of the following is true? (Only one is completely true.) a My mass is calculable from the speed because I know the acceleration due to gravity. b Not only can this information be used to calculate my mass; I don't even need to measure the speed to get it. c My mass is irrelevant to the problem, so there is no way I could calculate it from this information. d The speed and time give acceleration, but from this, I don't know the force on me so I cannot measure my mass. e Since the wall pushes back on me with the same magnitude force, knowing the speed and time gives me acceleration, so I can calculate my mass. f Since the wall pushes back on me with the same magnitude force, if I had measured the distance travelled in that second instead of the speed, then I could calculate my mass, but from this information I cannot. g Since the wall pushes back on me with the same magnitude force, if I had also measured the distance travelled in that second, then I could calculate my mass, but from this information I cannot. h This could almost be used to calculate my mass, but since energy is not conserved it will not work.
I stand on an ideal skateboard (there is no friction with the floor) and start from rest when I push on a wall with a known force, I measure my speed after one second. Which of the following is true?
(Only one is completely true.)
| a |
My mass is calculable from the speed because I know the acceleration due to gravity. |
|
| b |
Not only can this information be used to calculate my mass; I don't even need to measure the speed to get it. |
|
| c |
My mass is irrelevant to the problem, so there is no way I could calculate it from this information. |
|
| d |
The speed and time give acceleration, but from this, I don't know the force on me so I cannot measure my mass. |
|
| e |
Since the wall pushes back on me with the same magnitude force, knowing the speed and time gives me acceleration, so I can calculate my mass. |
|
| f |
Since the wall pushes back on me with the same magnitude force, if I had measured the distance travelled in that second instead of the speed, then I could calculate my mass, but from this information I cannot. |
|
| g |
Since the wall pushes back on me with the same magnitude force, if I had also measured the distance travelled in that second, then I could calculate my mass, but from this information I cannot. |
|
| h |
This could almost be used to calculate my mass, but since energy is not conserved it will not work. |
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