Construction Health And Safety Technician (CHST) Practice Test

To determine the speed of a 4-inch diameter grinding wheel operating at 12,000 rpm in surface feet per minute (SFM), you can use the following formula: SFM = (Diameter in inches × π × RPM) / 12 Here, the diameter of the wheel is 4 inches, and π is approximately 3.14159. First, we calculate the circumference of the wheel: Circumference = Diameter × π = 4 inches × 3.14159 = 12.56636 inches. Next, to convert this measurement to feet, since there are 12 inches in a foot, we divide by 12: Circumference in feet = 12.56636 inches / 12 = 1.0472 feet. Now, we multiply the circumference in feet by the rpm: SFM = 1.0472 feet × 12,000 rpm = 12,566.4 surface feet per minute. Rounding to the nearest whole number gives us approximately 12,566 surface feet per minute. This calculation confirms that the speed of the grinding wheel is indeed 12,566 surface feet per minute, making the choice that states this value accurate. Understanding the relationship between diameter,