I got these questions wrong. Can you please tell me the right answer but also sh
ID: 1602776 • Letter: I
Question
I got these questions wrong. Can you please tell me the right answer but also show me/explain how you got the right answer. Thanks !
Physics 151 Exam 1 100 Name AL at lfidun Note: the graphs below represent the motion of objects moving along a straight level path. The last graph is a VELOCITY graph. 1. The magnitude of the velocity of the object is decreasing in which of the cases? (A) ll only (B) III only (C) and II only land III on (E) I, II, and Ill 2. In which of the cases above is the acceleration positive? (A) I only (B) II only (C) only Only ll, and Ill 3. If A B-2 and their magnitudes are given by A B c, then the vectors and Bare oriented perpendicular relative to one ot (B) parallel to each other (in the same direction). (C) antiparallel to each other (in opposite directions. (D) It is impossible to know from the given information.Explanation / Answer
1) On x-t graph velocity is slope of the graph. If slope is +ve velocity +ve and vice versa.
In first graph slope is throught -ve and increasing. Hence velocity is -ve and and it's magnitude is increasing.
In second graph, slope is always +ve and decreasing. Hence velocity is +ve and it's magnitude is decreasing.
Third graph is V-t graph. Gralph is above time-axis, velocity is always +ve. Magnitude of velocity is increasing, as graph moves away from time-axis.
Hence option A is correct.
2) x-t graph, if not straight line, concave upward indicates +ve acceleration and concave downward indicates -ve acceleration. Both x-t graphs are concave downward, hence -ve acceleration.
In V-t graph sign of slope gives sign of acceleration. As slope of V-t graph is +ve hence acceleration is +ve.
Option C is correct.
3) As A + B = C
If A and B are not in same line, three vectors form a triangle. By properties of triangle
A + B > C,
A and B have to be in straight line.
Since A + B = C, A and B are parallel to each other
option B s correct.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.