Question #53965

2 Answers
Jun 19, 2017

See explanation.

Explanation:

We know that:

#vec(v)=15 m/s#

#t=1s#

#n=2#

The fact that it takes #1s# to complete 2 revolutions implies that the period is #T=0.5s#

If we know the velocity we can calculate that:

#s=v*T=15*0.5=7.5#

The circle's circomference is #s=7.5#, so the radius is:

#r=s/(2pi)#

#r=7.5/6.28~~1.2#

The correct answer is #B#

Jun 19, 2017

The answer is B) 1.2 m.

Explanation:

The problem says that it takes #1# second to go two revolutions. If the object is traveling at #15m/sec#, or #15# meters per #1# second, two revolutions are #15# meters total (#15m=2 revolutions).

Divide the revolutions by 2 to get the meters per revolution:
#15/2 m=2/2 revolutions-> 7.5 m = 1 revolution#

1 revolution is equal to the circumference of the circle (#2pir#) created by the object's motion, so:

#1 rev = 7.5 m = 2pir#

#7.5m = 2pir#

#7.5/(2pi)m = (2pir)/(2pi)#

#r = 7.5/(2pi) m#

#7.5/(2pi) = 1.193#

Round this to get 1.2 m as your answer.