Laying new sod When new sod is laid a heavy roller is used t

Laying new sod: When new sod is laid, a heavy roller is used to press the sod down to ensure good contact with eh ground beneath. The radius of the roller is 1ft. a)Through what angle (in radians) has the roller turned after being pulled across 5ft of yard? b)What angle must the roller turn through to press a length of 30ft?

Solution

In one roll roller moves ---- 2pi*r = 2*pi*1 = 2pi ft

a) No. of rolls = 5ft/2pi ft = 5/2pi = 0.79

1 roll--- 2pi radians

0.79 roll ---- 2pi*0.79 = 5 radians

b) No. of rolls = 30 ft / 2pi ft = 4.77

1 roll ---2pi radians

4.77 roll ---- 2pi*4.77 = 29.97 radians