Chapter 7. Acceleration vector equals change in velocity vector divided by time interval (3-9)

Question

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{"title":"acceleration vector for the object over a very short time interval from t sub 1 to a later time t sub 2","description":"Correct!","type":"correct","color":"#99CCFF","code":"[{\"shape\":\"rect\",\"coords\":\"1,38,24,72\"},{\"shape\":\"poly\",\"coords\":\"82,133\"}]"} {"title":"change in velocity of the object over the short time interval","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"76,7,132,49\"},{\"shape\":\"rect\",\"coords\":\"118,11,119,13\"}]"} {"title":"elapsed time for the time interval","description":"Incorrect","type":"incorrect","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"80,71,117,100\"},{\"shape\":\"poly\",\"coords\":\"113,132\"}]"} {"title":"for both the velocity change and the elapsed time, subtract the earlier value from the later value","description":"Incorrect","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"260,5,297,53\"},{\"shape\":\"rect\",\"coords\":\"254,68,293,118\"}]"}

Question

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{"title":"acceleration vector for the object over a very short time interval from t sub 1 to a later time t sub 2","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"rect\",\"coords\":\"1,38,24,72\"},{\"shape\":\"poly\",\"coords\":\"82,133\"}]"} {"title":"change in velocity of the object over the short time interval","description":"Correct!","type":"correct","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"76,7,132,49\"},{\"shape\":\"rect\",\"coords\":\"118,11,119,13\"}]"} {"title":"elapsed time for the time interval","description":"Incorrect","type":"incorrect","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"80,71,117,100\"},{\"shape\":\"poly\",\"coords\":\"113,132\"}]"} {"title":"for both the velocity change and the elapsed time, subtract the earlier value from the later value","description":"Incorrect","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"260,5,297,53\"},{\"shape\":\"rect\",\"coords\":\"254,68,293,118\"}]"}

Question

PWb9m2eWN01q/vsUCvM700KfvgIoKoaaxlk4fgPG5gdYMHqG8MV0qEIX1Bc5DjdVQ/u5eg==

{"title":"acceleration vector for the object over a very short time interval from t sub 1 to a later time t sub 2","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"rect\",\"coords\":\"1,38,24,72\"},{\"shape\":\"poly\",\"coords\":\"82,133\"}]"} {"title":"change in velocity of the object over the short time interval","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"76,7,132,49\"},{\"shape\":\"rect\",\"coords\":\"118,11,119,13\"}]"} {"title":"elapsed time for the time interval","description":"Correct!","type":"correct","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"80,71,117,100\"},{\"shape\":\"poly\",\"coords\":\"113,132\"}]"} {"title":"for both the velocity change and the elapsed time, subtract the earlier value from the later value","description":"Incorrect","type":"incorrect","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"260,5,297,53\"},{\"shape\":\"rect\",\"coords\":\"254,68,293,118\"}]"}

Question

wwmSY2u92XIp/1F77IWBij6GfdgzV5s4hYyMZzPYjp47+BmJAzjkOaPCAUN8gKwLrkDcg4dcpPrNu7Fn/wEacBiMP75KCCFt5s3b0KXLWYWXOLYQBcOkKH7laL+9knBH6UKjBc5bQlMVBkiC

{"title":"acceleration vector for the object over a very short time interval from t sub 1 to a later time t sub 2","description":"Incorrect","type":"incorrect","color":"#99CCFF","code":"[{\"shape\":\"rect\",\"coords\":\"1,38,24,72\"},{\"shape\":\"poly\",\"coords\":\"82,133\"}]"} {"title":"change in velocity of the object over the short time interval","description":"Wrong","type":"incorrect","color":"#ffcc00","code":"[{\"shape\":\"rect\",\"coords\":\"76,7,132,49\"},{\"shape\":\"rect\",\"coords\":\"118,11,119,13\"}]"} {"title":"elapsed time for the time interval","description":"Wrong","type":"incorrect","color":"#333300","code":"[{\"shape\":\"rect\",\"coords\":\"80,71,117,100\"},{\"shape\":\"poly\",\"coords\":\"113,132\"}]"} {"title":"for both the velocity change and the elapsed time, subtract the earlier value from the later value","description":"Correct!","type":"correct","color":"#000080","code":"[{\"shape\":\"rect\",\"coords\":\"260,5,297,53\"},{\"shape\":\"rect\",\"coords\":\"254,68,293,118\"}]"}

Review

Equations 7-1 involve the \(\textit{accelerations}\) of the skateboard and you, but we’re interested in the velocities of the skateboard and you after the push-off. To see how to get these, let’s go back to the definition of the acceleration vector in Section 3-5. This definition tells us that