phys11_sm_01_r
phys11_sm_01_r
phys11_sm_01_r
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26. Given:<br />
Required: ! ! d T<br />
!<br />
d inital = 76 km [W];<br />
Analysis: ! ! d T = ! d final ! ! d inital<br />
Solution:<br />
! ! d T = ! d final ! ! d inital<br />
= 54 km [E] ! 76 km [W]<br />
= 54 km [E] + 76 km [E]<br />
! ! d T = 130 km [E]<br />
!<br />
d final = 54 km [E]<br />
Statement: The car’s displacement is 130 km [E].<br />
27. Given: ∆d = 250 m; ∆t = 4.0 s<br />
Required: vav<br />
Analysis:<br />
Solution:<br />
! d<br />
v = av<br />
!t<br />
! d<br />
v = av<br />
!t<br />
= 250 m<br />
4.0 s<br />
v = 63 m/s<br />
av<br />
Statement: The race car’s average speed is<br />
63 m/s.<br />
28. Given: vav = 15 m/s; ∆t = 3.0 s<br />
Required: ∆d<br />
! d<br />
Analysis: v = av<br />
!t<br />
! d = v !t av<br />
Solution:<br />
! d = v av !t<br />
= 15 m ! $<br />
"<br />
# s %<br />
& 3.0 s<br />
( )<br />
! d = 45 m<br />
Statement: The baseball will go 45 m in 3.0 s.<br />
!<br />
29. Given: ∆ d = 310 m [S]; ∆t = 8.0 s<br />
!<br />
Required:<br />
Analysis:<br />
Solution:<br />
v av<br />
!<br />
v av = ! ! d<br />
!t<br />
!<br />
v = av ! ! d<br />
!t<br />
= 310 m [S]<br />
8.0 s<br />
!<br />
v = 39 m/s [S]<br />
av<br />
Statement: The average velocity of the bird is<br />
39 m/s [S].<br />
30. Given:<br />
∆t = 1.2 h<br />
Required:<br />
Analysis:<br />
Solution:<br />
!<br />
d inital = 45 km [W];<br />
!<br />
d final = 15 km [E];<br />
Copyright © 2<strong>01</strong>1 Nelson Education Ltd. Chapter 1: Motion in a Straight Line 1-3<br />
!<br />
v av<br />
!<br />
v = av ! ! d<br />
!t<br />
!<br />
! d ! final<br />
v = av ! dinitial !t<br />
!<br />
! d ! final<br />
v = av ! dinitial !t<br />
= 15 km [E] ! 45 km [W]<br />
1.2 h<br />
= 15 km [E] + 45 km [E]<br />
1.2 h<br />
= 60 km [E]<br />
!<br />
#<br />
"<br />
1.2 h<br />
$ ! 1000 m $<br />
& # &<br />
% " 1 km %<br />
= 60 000 m [E]<br />
!<br />
$ ! 1 h $ ! 1 min<br />
"<br />
# 1.2 h %<br />
& # & #<br />
" 60 min % " 60 s<br />
!<br />
v = 14 m/s [E]<br />
av<br />
Statement: The velocity of the car is 14 m/s [E].<br />
!<br />
!<br />
31. Given: ∆ d = 2400 m [W]; v = 9.0 m/s [W]<br />
av<br />
Required: ∆t<br />
!<br />
Analysis: v = av ! ! d<br />
!t<br />
!t = ! ! d<br />
!<br />
vav Solution:<br />
!t = ! ! d<br />
!<br />
vav = 2400 m [W]<br />
9.0 m<br />
s [W]<br />
!t = 2.7 ! 10 2 s<br />
Statement: The bird is in flight for 2.7 × 10 2 s or<br />
270 s.<br />
32. Given: vav = 251 km/h; ∆t = 14.3 s<br />
Required: ∆d<br />
Analysis:<br />
Solution:<br />
! d = v av !t<br />
! d<br />
v = av<br />
!t<br />
! d = v !t av<br />
= 251 km ! $ ! 1 h $ ! 1 min<br />
"<br />
# h %<br />
& ( 14.3 s ) # & #<br />
" 60 min % " 60 s<br />
! d = 0.997 km<br />
$<br />
&<br />
%<br />
$<br />
&<br />
%