University:
College Entrance Preparation
Course:
ACT Preparation (Science)
Academic year:

2021
Views:

249

Pages:

11
Author:

Apolenajz

Motion Graphs 1 Name Motion Graphs Describing the motion of an object is occasionally hard to do with words. Sometimes graphs help make motion easier to picture, and therefore understand. Remember: • Motion is a change in position measured by distance and time. • Speed tells us the rate at which an object moves. • Velocity tells the speed and direction of a moving object. • Acceleration tells us the rate speed or direction changes. DISTANCE- TIME GRAPHS fllso u c\ ce, rv\ z \rr { - rvwe. Plotting distance against time can tell you a lot about motion. Let's look at the axes: Time is always plotted on the X-axis ( bottom of the graph). The further to the right on the axis, the longer the time from the start. o S ft Distance is plotted on the Y-axis ( side of the graph). The higher up the graph, the further from the start. Time If an object is not moving, a horizontal line is shown on a distance-time graph. Time is increasing to the right, but its distance does not change. It is not moving. We say it is At Rest. o a • ^ ft Time M. Poarch - 2003 http: // nee-clas s.net Motion Graphs 2 If an object is moving at a constant speed, it means it has the same increase in distance in a given time: Time is increasing to the right, and distance is increasing constantly with time. The object moves at a constant speed . o Si Constant speed is shown by straight lines on a graph. o Let's look at two moving objects: Both of the lines in the graph show that each object moved the same distance, but the steeper dashed line got there before the other one: A steeper line indicates a larger distance moved in a given time. In other words, higher speed . o § Both lines are straight, so both speeds are constant. Q Graphs that show acceleration look different from those that show constant speed. The line on this graph is curving upwards. This shows an increase m speed, since the line is getting steeper: o § ft In other words, in a given time, the distance the object moves is change (getting larger). It is acceleratinq. Time M. Poarch - 2003 http: //science-class , net Motion Graphs 3 Summary: A distance-time graph tells us how far an object has moved with time. • The steeper the graph, the faster the motion. • A horizontal line means the object is not changing its position - it is not moving, it is at rest. • A downward sloping line means the object is returning to the start. A i ; fast; s eady S seed. I ; UJ ! j 1 i t .< h- m gelling faster i O a I i ! steadv j stationary A speed : I retiming : J. — : : - to start ; TIME ( from: http:// www.bbc.co.uk/ schools / qcsebitesize / / for / speedvelocitvaccelerationfhrev 2.shtmn M. Poarch - 2003 http: //science-class , net Motion Graphs 4 Examine the graphs below. -aw- 40 * *- X > T t n >> c a * c 30 u ra w 20 H I ® 1 . 2 3 4 Time (in seconds) 40 uT o • 0 Ei 1 2 4 3 Time (in seconds) --a — m 40 - L rn fa >J c m C I ! a> 30 u at u c J3 30 c rn in D CJ 21 20 10 10 i : • 2 C f 4 3 1 D Time (in seconds ) 4 3 2 Time (in seconds) Which of the graphs shows that one of runners started 10 yards further ahead of the other? Explain your answer. Uf> to /( \r £ •' TUi . <£} Vw_pUc, -s4-ztWVw ^^ SktfWS cTVw^. . CKJO CK~\S ^ Tue . TU_*_ l _£_o-e_ Tv—«_ % UP ^ 40 T3 ITS C S 30 ns - — +* ) in D 20 J 1 f Time (in seconds } ^ 40 3 4 m 40 "O m . s d S 2 Time (in seconds } “ . T3 TO 0 B if /-s 1 : 30 d: S c 313 c re re tn Ln D D 2i i i : 1——i—i 20 1 ; { : n '•••" ; i I ; 1 — i > i n ; ? i :: 0 1 2 3 ; 4 Time (in seconds } C M. Poarch - 2003 http: //science-class.net 1 2 3 4 Time (in seconds) Motion Graphs 6 The distance-time graphs below represent the motion of a car. Match the descriptions with the graphs. Explain your answers. Descriptions: 1. The car is stopped. C - rui 2. The car is traveling at a constant speed. 3. The speed of the car is decreasing, D 4. The car is coming back. _s.fru- .e- /3 ~ ^ - B> CWO Graph F matches description % because i Graph G matches description G> because Is Ktof r U /\ Graph H matches description because S 'C -eei \s ^ M. Poarch - 2003 http. //science-class net , . ^ ! wca • . Motion Graphs 10 Questions: ( Some questions adapted from http:// www.bbc.co.uk / schools / qcsebitesize / p /forces/ speedvelocitvaccelerationfhrev 2.shtmn n * r Albert Bob Charlie i V, . U hs © ""I T w How long did Bob take to complete the race? Explain your answer. < 'I4. K- O Calculate Albert's average speed. (Figure the distance_and the time first!) -^t ~ “ ICO h* 12. M. Poarch - 2003 http: //science-class,net ^ TUOJ ' ' ( ociwrf SO ' Motion Graphs 11 The graph below shows how the speed of a bus changes during part of a journey fttfrf '.•Ilf tXKJKt i . A 10 m .: B s f s ; Q UJ UJ 0 ( - 4 F U) 2 o 0 0 c 2 4 6 S 10 12 D 16 14 12 20 22 24 25 TIME i;$eeor«&} Choose the correct words from the following list to describe the motion during each segment of the journey to fill in the blanks. • • • • accelerating decelerating constant speed at rest Segment 0- A The bus is from 0 to 10 m/ s in 5 seconds. . Its speed changes ArOc-ei^v-gt-fi~ Segment A- B The bus is moving at a of 10 m/s for 5 seconds. Segment B- C The bus is c&L&rzx -bi down from 10 m/ s to rest in 3 seconds. Segment C- D The bus is . It is slowing 3 aJr . It has stopped. Segment D- E The bus is 3 It is gradually increasing in speed. M. Poarch - 2003 http: //science-class net ,