A fan has four blades attached to a central shaft. The blades are lf = 17 cm long and each blade have a uniformly distributed mass of mf = 0.11 kg. The fan spins up from rest to an angular speed of ωf = 111 rad/s in tf = 0.85 s.Give an expression for the average torque τf that the fan’s motor exerts on the fan as it spins up. τ = The image displays a keypad layout with a combination of Greek letters and mathematical symbols on the left side and numbers with additional function keys on the right side.### Left Section:This section contains a grid of Greek letters and mathematical symbols organized in four rows and three columns:1. **First Row:** - α (alpha) - β (beta) - ΔL (change in length)2. **Second Row:** - ΔLf (final change in length) - ωf (final angular velocity) - θ (theta)3. **Third Row:** - d (distance) - g (acceleration due to gravity) - h (height)4. **Fourth Row:** - j (current density) - k (thermal conductivity) - m (mass)5. **Fifth Row:** - P (power) - t (time) - tf (final time)### Right Section:This section comprises a numeric keypad along with additional function keys:- Numbers arranged in a typical keypad format: - Top Row: 7, 8, 9, with "HOME" - Second Row: 4, 5, 6, with an arrow pointing left - Third Row: 1, 2, 3, with an arrow pointing right - Bottom Row: plus (+), minus (-), 0, with "END"- Additional Keys: - Leftmost column includes: - ( (open parenthesis), ) (close parenthesis) - ↑ (up arrow), ↓ (down arrow) - / (division), * (multiplication) - √ (square root), O (possibly zero or symbol) - Bottom right corner: - BACKSPACE - DEL (delete) - CLEARThis grid appears to serve as a mathematical input tool, likely intended for use in scientific or mathematical educational software for calculations or symbolic representations.

Total number of blade Length of each blade Mass of each blade Initial angular speed Final angular speed Time interval The average torque acting on the fan can be expressed as (1)Where,I=Moment of inertiaAngular accelerationNow, the moment of inertia of each rod rotating around the central shaft is Where,mf=Mass of each bladelf=Length of each bladeSo, the total moment of inertia for the four blade will be (2)The angular acceleration is expressed asWhere,Final angular speedInitial angular speedTimeNow, since the blade started from rest so, the initial speed will be zero, So, (3)So, from equation (1), (2) and (3)Now, substituting the given values The expression for the average torque is the numerical value is 0.55 N.m