Torque = r x F
|F| = mg = 60 * 10 N = 600 N ( assuming g ~ 10m/s^2)
distance of fulcrum = torque / Force = 90/600 m = .15 m.
Absorption occurs when <span>all of the energy from light waves is transferred to a medium! </span>
Answer:

Explanation:
Given:
mass of first particle, 
mass of second particle, 
mass of third particle, 
coordinate position of first particle in meters, 
coordinate position of second particle in meters, 
coordinate position of third particle in meters, 
<u>Now, gravitational force on particle 3 due to particle 1:</u>



towards positive Y axis.
<u>gravitational force on particle 3 due to particle 2:</u>



towards positive X axis.
<u>Now the net force</u>



<em>For angle in counterclockwise direction from the +x-axis</em>

<span>The change in internal energy is only gravitional PE because the tube is being drug up at a constant speed. Since it is at a constant speed, the change in KE is 0.
Change in PE = m*g*h = 78 kg * 10 m/s^2 * 30 m = 23400 J
Work done on the system is from the force
Work = force * distance = 350 N * 120 m = 42000 J
So, work added 42000 J to the system, but the rider's energy only increased 23400 J. Therefore, friction took up the difference. Friction is where the thermal energy comes from
Q = 42000 J - 23400 J = 18600 J.
Therfore, friction generated 18600 J of heat to the surroundings.</span>