C7M.7 A safety table saw uses a braking system to stop the saw blade from rotating if it senses that the blade is touch- ing the user's finger. To avoid injuring the finger, the blade must be stopped within the time it would take the blade to rotate about 1/20 of a turn at full speed. Assume the saw blade is essentially a flat disk with mass M and radius R, and rotates once in time T at full speed. (a) What is the magnitude F of the constant force that the brake must exert on the rim when tripped in terms of these quantities? (b) If the saw blade has a radius of 13 cm, a mass of 600 g, and rotates at 3000 rpm, what is F? (The braking sys- tem used in safety saws exerts this enormous force by jamming a soft aluminum block into the blade's teeth. The force is exerted as a result of the teeth burying themselves in the block.) Figur Perfor and n If w forr veci by t can no