Post on 14-Jan-2016
Motion in One DimensionProblems MC Questions
2
A motorcycle is moving with a speed v when the rider applies the brakes, giving the motorcycle a constant deceleration. During a time t, immediately after braking begins, the speed decreases to v/2. What distance does the motorcycle travel from the instant braking begins until the motorcycle stops?
Stopping a motorcycle 1
2
2
t
v )E(
tv
)D( vt )C( vt )B( t
v )A(
Let v = 22.0 m/s and t = 4.00 s, calculate the distance required to stop the motorcycle.
m 88 )E( m 48 )D(
m 87 )C( m 47 )B( m 86 )A(
A sprinter acquires a top speed v while running a race length D. If the sprinter starts from rest and accelerates at a constant rate, he is able to reach his top speed in a distance d. He is then able to maintain this top speed for the remainder of the race. What is his time required for the sprinter to run the race?
Running a Race 2
vd
)E( v
dD )D(
2vdD
)C( vD
)B( v
dD )A(
If v = 11.0 m/s, d = 12 m, and D = 100 m, calculate the time required for the sprinter to run the race.
s 0.41 )E( s 0.21 )D(
s 0.01 )C( s .89 )B( s .69 )A(
On a dry road a car with good tires is able to brake with a
constant deceleration of 4.92 m/s2. If the car is initially traveling at 24.6 m/s,(a) how much time is required to stop?
3
s 52 )E( s 02 )D(
s 51 )C( s 01 )B( s .05 )A(
(b) how far does it travel in this time?
m 07 )E( m 66 )D(
m 26 )C( m 85 )B( m 45 )A(
The maximum acceleration of a subway train is , and subway stations are located a distance d apart, (a) what is the maximum speed a subway train can attain between stations?
a
4
da )E( da
)D(
ad
)C( da )B( ad
)A(
(b) what is the travel time between stations?
ad
2 )E( ad2 )D(
ad
)C( da
2 )B( da
)A(
Solutions
A motorcycle is moving with a speed v when the rider applies the brakes, giving the motorcycle a constant deceleration. During a time t, immediately after braking begins, the speed decreases to v/2. What distance does the motorcycle travel from the instant braking begins until the motorcycle stops?
ax2vv 2o
2
x t2
v2v0 2
t2v
a
t
v2v
a
vtx
Stopping a motorcycle
vv0v
o
tv
a
1
A motorcycle is moving with a speed of 22.0 m/s when the rider applies the brakes, giving the motorcycle a constant deceleration. During a time of 4.00 s, immediately after braking begins, the speed decreases to 11.0 m/s. What distance does the motorcycle travel from the instant braking begins until the motorcycle stops?
vtx
Stopping a motorcycle
s 4.00 m/s 22.0x
m .088x
1
t 2
vvx fi
v
tt1 t2
dD d
vd2
t1
tx
v
21 ttt
The time required to run the race t = t1 + t2
Running a Race
1t 2v0
d
2tdD
v
vdD
t2
vdD
vd2
t
vdD
t
During acceleration Constant speed
2
The time required for the sprinter to run the race?
Running a Race
vdD
t
11
tt1 t2
12 m88 m
m/s 11m 12m 100
t s 2.10
2
On a dry road a car with good tires is able to brake
with a constant deceleration of 4.92 m/s2. If the car is initially traveling at 24.6 m/s,(a) The time required to stop the car.
atvv o
a
vt o 2m/s 4.92
m/s 24.6
s 0.5t
atv0 o
3
On a dry road a car with good tires is able to brake
with a constant deceleration of 4.92 m/s2. If the car is initially traveling at 24.6 m/s,(b) The distance the car travels in this time.
ax2vv 2o
2
a2
vx
2o
2
2
m/s .9242
m/s 24.6
m 5.61x
3
ax2v0 2o
2
ax2vv 2o
2
advmax
vmax
t
a
(s)
2d
2d
2d
a20v 22max
a) The maximum speed a subway train can attain between stations4
2at
tvx2
o
ad
th
vmax
t
a
(s)
2d
2d
2
att0
2d 2
hh
a) The travel time between stations.
Time to travel half way
ad
2t2t htotal
4
Total time for trip