To solve this exercise we need the concept of Kinetic Energy and its respective change: Initial and final kinetic energy.
Let's start considering that the angular velocity is given by,
Where,
V = linear speed
R = the radius
In the case of the initial kinetic energy:
Where I is the moment of inertia previously defined.
In the case of the final kinetic energy, we have to,
For conservation of Energy we have, that
, then (canceling the mass and the radius)
There are many ways to solve this but I prefer to use the energy method. Calculate the potential energy using the point then from Potential Energy convert to Kinetic Energy at each points.
PE = KE
From the given points (h1 = 45, h2 = 16, h<span>3 </span>= 26)
Let’s use the formula:
v2= sqrt[2*Gravity*h1] where the gravity is equal to 9.81m/s2
v3= sqrt[2*Gravity*(h1 - h3 )] where the gravity is equal to 9.81m/s2
v4= sqrt[2*Gravity*(h1 – h2)] where the gravity is equal to 9.81m/s2
Solve for v2
v2= sqrt[2*Gravity*h1]
= √2*9.81m/s2*45m
v2= 29.71m/s
v3= sqrt[2*Gravity*(h1 - h3 )
=√2*9.81m/s2*(45-26)
=√2*9.81m/s2*19
v3=19.31m/s
v4= sqrt[2*Gravity*(h1 – h2)]
=√2*9.81m/s2*(45-16)
=√2*9.81m/s2*(29)
v4=23.85m/s
It is the speed with direction. (Ex. The car is going 4 mph south)
It increases in temperature