ANSWERS: 3

Calculate the gain in energy it takes to raise her from the bottom of the arc to the 45 degrees angle using a diagram some trig and the equation Potential Energy, PE = mgh. At the top, her Kinetic Energy is zero. Then as she drops again, (nearly) all that Potential Energy must become Kinetic Energy again, so use the KE equation, KE=(1/2)mv^2 to find the speed.

40m/s

KE high + PE high = KE low + PE low 0 + mgl(1costheta)=1/2 mv^2 + 0 mass cancels out leaving gl(1costheta)=1/2 v^2 thus Sq.rt of 2(g)(l)(1cos theta) 2(9.8)(3)(1cos45)= 4.1 m/s
Copyright 2020, Wired Ivy, LLC