phys11_sm_01_r
phys11_sm_01_r
phys11_sm_01_r
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Statement: The average velocity of the racer<br />
between the checkpoints is 19 m/s [W].<br />
!<br />
!<br />
49. Given: d = 450 km [W]; d = 920 km [W];<br />
1 2<br />
!<br />
v = 40.0 km/h [W]<br />
av<br />
Required: ∆t<br />
!<br />
Analysis: v = av ! ! d<br />
!t<br />
!<br />
! d ! 2<br />
v = av ! d1 !t<br />
!<br />
d ! 2<br />
!t =<br />
! d1 !<br />
Solution:<br />
!t =<br />
v av<br />
!<br />
d 2 ! ! d 1<br />
!<br />
v av<br />
= 920 km [W] ! 450 km [W]<br />
40.0 km<br />
h [W]<br />
!t = 12 h<br />
Statement: It will take the train 12 h to travel<br />
between the two stations.<br />
!<br />
!<br />
50. Given: d = 4.5 km [S]; d = 2.5 km [N];<br />
1 2<br />
vav = 9.7 m/s<br />
Required: ∆t<br />
!<br />
Analysis: v = av ! ! d<br />
!t<br />
!<br />
! d ! 2<br />
v = av ! d1 !t<br />
!<br />
d ! 2<br />
!t =<br />
! d1 !<br />
v av<br />
!<br />
d ! 2 Solution: !t =<br />
! d1 !<br />
vav = 2.5 km [N] ! 4.5 km [S]<br />
9.7 m/s<br />
= 2.5 km [N] + 4.5 km [N]<br />
9.7 m/s<br />
= 7.0 km [N]<br />
9.7 m<br />
" 1000 m % " 1 min%<br />
$ '<br />
# 1 km & #<br />
$ 60 s &<br />
'<br />
s<br />
!t = 12 min<br />
Statement: The trip will take him 12 min.<br />
51. Given: vi = 1.0 m/s; vf = 7.6 m/s;<br />
∆t = 0.8 s<br />
Required:<br />
Analysis:<br />
Solution:<br />
Copyright © 2<strong>01</strong>1 Nelson Education Ltd. Chapter 1: Motion in a Straight Line 1-7<br />
!<br />
a av<br />
a av = v f ! v i<br />
!t<br />
a = av vf ! vi !t<br />
= 7.6 m/s ! 1.0 m/s<br />
0.8 s<br />
a = 8.3 m/s av 2<br />
Statement: The acceleration of the deer is<br />
8.3 m/s 2 .<br />
!<br />
!<br />
52. Given: v = 7.0 m/s [W]; v = 12.1 m/s [W];<br />
i f<br />
!<br />
a = 3.9 m/s av 2 [W]<br />
Required: ∆t<br />
!<br />
! v ! f Analysis: a = av ! vi !t<br />
!<br />
v ! f<br />
!t =<br />
! vi !<br />
Solution:<br />
!t =<br />
= 12.1 m/s [W] ! 7.0 m/s [W]<br />
a av<br />
!<br />
v f ! ! v i<br />
!<br />
a av<br />
3.9 m/s 2 [W]<br />
5.1<br />
=<br />
m<br />
s [W]<br />
3.9 m<br />
[W] 2<br />
s<br />
!t = 1.3 s<br />
Statement: It takes 1.3 s for the motorcycle to<br />
accelerate.<br />
!<br />
53. Given: v = 32.0 m/s [down];<br />
i<br />
!<br />
v = 24.0 m/s [up]; ∆t = 5.30 s<br />
f<br />
!<br />
Required: aav !<br />
! v ! f Analysis: a = av ! vi !t<br />
!<br />
! v ! f Solution: a = av ! vi !t<br />
= 24.0 m/s [up] ! 32.0 m/s [down]<br />
5.30 s<br />
= 24.0 m/s [up] + 32.0 m/s [up]<br />
5.30 s<br />
!<br />
a = 10.6 m/s av 2 [up]<br />
Statement: The average acceleration of the<br />
bungee jumper is 10.6 m/s 2 [up].