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Consider an old-fashion bicycle with a small wheel of radius 0.17 m and a large wheel of radius 0.92 m. Suppose the rider starts at rest, accelerates with a constant acceleration for 2.7 minutes to a velocity of magnitude 10 m/s. He maintains this velocity for 13.7 minutes and then accelerates, with a constant deceleration, for 4.1 minutes at which time he is at rest. Find the total distance traveled by the rider. Give your answer in kilometers.

asked
User Ympostor
by
7.9k points

2 Answers

1 vote

Answer:


s=10.26\ km

Step-by-step explanation:

Given

initial velocity of bicycle,
u=0\ m.s^(-1)

velocity of the bicycle after the first phase of acceleration,
v_1=10\ m.s^(-1)

duration of first phase of uniform acceleration,
t_1=2.7\ min=162\ s

duration of second phase of zero acceleration,
t_2=13.7\ min=822\ s

uniform velocity during the second phase,
v_2=10\ m.s^(-1)

duration third phase of uniform deceleration,
t_3=4.1\ min=246\ s

final velocity after the third phase of motion,
v=0\ m.s^(-1)

  • Now we find the acceleration in the first phase of motion:


a_1=(v_1-u)/(t_1)


a_1=(10-0)/(162) =(10)/(162)\ m.s^(-2)

Now using the equation of motion:


s_1=u.t_1+0.5a_1.t_1^2


s_1=0+0.5* (10)/(162) * 162^2


s_1=810\ m is the distance covered in the first phase of motion.

  • Distance covered in the third phase of motion:


s_2=v_2* t_2


s_2=10* 822


s_2=8220\ m

  • Now we find the deceleration in the third phase of motion:


a_3=(v-v_3)/(t_3)


a_3=(0-10)/(246)


a_3=(10)/(246)\ m.s^(-1)

Now using the equation of motion:


s_3=v_3.t_3+05.* a_3.t_3^2


s_3=10* 246-0.5* (10)/(246) * 246^2


s_3=1230\ m is the distance covered in the third phase of motion.

Hence the total distance covered by the bicycle in the whole incident is:


s=s_1+s_2+s_3


s=810+8220+1230


s=10260\ m


s=10.26\ km

answered
User Gilseung Ahn
by
7.5k points
2 votes

Answer:

10259.6 m

Step-by-step explanation:

We are given that

Radius of small wheel,r=0.17 m

Radius of large wheel,r'=0.92 m

Initial velocity,u=0

Time,t=2.7 minutes=162 s

1 min=60 s

Velocity,v=10m/s

Time,t'=13.7 minutes=822 s

Time,t''=4.1 minutes=246 s


v=u+at

Substitute the values


10=0+162a=162a


a=(10)/(162)=0.0617m/s^2


s=ut+(1)/(2)at^2

Substitute the values


s=(1)/(2)(0.0617)(162)^2=809.6 m


s'=vt'=10* 822=8220 m


a'=(v)/(t'')=(10)/(246)


s''=(1)/(2)a't''^2=(1)/(2)* (10)/(246)(246)^2=1230 m

Total distance traveled by rider=s+s'+s''=809.6+8220+1230=10259.6 m

answered
User Sibel
by
8.3k points

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