How many rotations per minute must a wheel of diameter 1.5 m make to achieve a…

Given: diameter = 1.5 m, required speed = 45 km/h.

Step 1: Convert speed to meters per minute: 45 × 1000 / 60 = 750 m/min.

Step 2: Distance covered in one rotation = circumference = π × 1.5 m

Step 3: Rotations per minute = (linear speed in m/min) / (circumference) = 750 / (π × 1.5) = 500/π

Numeric value: 500/π ≈ 159.16, which rounds to 160 rotations per minute.

Answer: 160 rotations per minute (approximately).