Describing velocity changes: In each of the following situations you will be ask
ID: 1327207 • Letter: D
Question
Describing velocity changes: In each of the following situations you will be asked to refer to the mathematical definitions and the concepts associated with the number line. Note that being more positive is the same as being less negative, and being less positive is the same as being more negative.
(a) Suppose an object undergoes a change in velocity from +2 m/s xˆ to +3 m/s xˆ . Is its velocity becoming more positive or less positive? What is meant by more positive? less positive?
(b) Suppose an object undergoes a change in velocity from +3 m/s xˆ to +2 m/s xˆ . Is its velocity becoming more positive or less positive? What is meant by more positive? less positive?
(c) Suppose an object undergoes a change in velocity from –3 m/s xˆ to –2 m/s xˆ . Is its velocity becoming more positive or less positive? What is meant by more positive? less positive? Physics 211 Homework Problems Page 2 Unit 4: One-Dimensional Motion II A Mathematical Description of Constant Acceleration
(d) Suppose an object undergoes a change in velocity from –2 m/s xˆ to –3 m/s xˆ . Is its velocity becoming more positive or less positive? What is meant by more positive? Less positive?
(e) Suppose an object is turning around so that it undergoes a change in velocity from –2 m/s xˆ to +2 m/s xˆ . Is its velocity becoming more positive or less positive than it was before? What is meant by more positive? Less positive? Is it undergoing an acceleration while it is turning around?
(f) Suppose an object is turning around so that it undergoes a change in velocity from +2 m/s xˆ to –2 m/s xˆ . Is its velocity becoming more positive or less positive than it was before? What is meant by more positive? Less positive? Is it undergoing an acceleration while it is turning around?
(g) What does it mean to say that an object undergoes a deceleration? Can this term be used without ambiguity?
Explanation / Answer
(a) the velocity is becoming more positive, which means that the body is accelerating
(b) velocity is becoming less positive , which means the body is slowing down or de-accelerating
(c) change in velocity from –3 m/s xˆ to –2 m/s xˆ . its velocity becoming more positive .But the negative sign shows the direction onlyy, the body here deaacelerates
(d) e an object undergoes a change in velocity from –2 m/s xˆ to –3 m/s xˆ . its velocity becoming less positive,which means that it is increasing its velocity in the -ve x axis ,or accelerating along -ve x-axis
(e) change in velocity from –2 m/s xˆ to +2 m/s xˆ . its velocity becoming more positive than it was before
we can say that it is deaccelerating upto 0 and the accelerates from 0 to +2
(f) its velocity becoming less positive than it was before , initially it undegoes deacceleration and den accelerates in the opposite direction
(g)a object undergoes deacceleration when its velocity is decreasing ,u can say that till (final -initial ) /time value is negative the body is deacceleraating