An athlete is performing squats in the weight room. The knee is going from anatomical position to 92 degrees and then back to anatomical position each squat. The athlete performs a total of 10 squats. This is done over a time period of 30 seconds. What is the angular acceleration (rad/sec 2) of the knee

  α = 0.357 ras / s²

Explanation:

This is a rotational kinematics exercise, it tells us that it performs 10 squats in 30 s, for which it performs one squat at t = 3 s, also indicates that the angle of the squat is θ = 92º

            θ = θ₀ + w₀ t + ½ α t²

the athlete starts from rest, whereby w₀ = 0 and the initial angle in the vertical position is zero (θ₀=0)

            θ = ½ α t²

            α = 2 θ /t²

let's reduce the magnitudes to the SI system

            θ = 92º (π rad /180º) = 0.511π rad

let's calculate

            α = 2 0.5111π /3²

            α = 0.1136π rad / s²

            α = 0.357 ras / s²

gas and liquid