It would take 15 trips. 90 divided by 6 is 15. Take that 15 and divide 225 which leaves you with 15
The South based its economy on the use of slaves for agricultural production of things like cotton and tobacco. The North had significant amounts of industry and other finished goods. The South could supply some of the raw materials for the industry of the North. Regardless, the North relied on paid labor.
Both groups thought they could get rich and powerful by exploiting ignorance of middle America. Oh, that's not an answer. Truth!
NOTE: Check your formula sheet if you have one these are often there.
Ac =

= rω^2
We know r = 4.00m
but what is ω?
ω =

= 2π*f
f is our frequency. we want it in seconds so we can divide by 60.
300/60 = 5rev/s
Ac = rω^2 = (4)(5)^2 = 100m/s
(b) Linear speed or v is equal to v = ω = (5)(4) = 20m/s
340 / 20 = 17
The speed of sound is 17 times faster.
NOTE: finished physics so i might be rusty and use an equation wrong. Tell me if something doesnt make sense. Im still new to this myself.