John and Joan walk in opposite directions around a circular path, starting from the same point. The path has a radius of 50.0 meters. John walks at 1.00 m/s, Joan at 1.25 m/s. How long will it take for them to meet?

Can someone please explain this to me?! I keep getting it wrong and I only have one try left!

1 answer

John: v1 = 1 m/s, distance “x”
Joan: v2=1.25 m/s, distance (2πR-x).
t= x/v1 =(2πR-x)/v2.
v2•x =(2πR-x) •v1 = 2πR•v1- v1•x,
x(v1+v2)= 2πR•v1,
x=2πR•v1/(v1+v2)=2•π•50•1/2.25=139.6 m.
t= x/v1=139.6/1 = 139.6 c.