Answer:


Explanation:
Given that.
Force acting on the particle, 
Position of the particle, 
To find,
(a) Torque on the particle about the origin.
(b) The angle between the directions of r and F
Solution,
(a) Torque acting on the particle is a scalar quantity. It is given by the cross product of force and position. It is given by :




So, the torque on the particle about the origin is (32 N-m).
(b) Magnitude of r, 
Magnitude of F, 
Using dot product formula,




Therefore, this is the required solution.
Basically, the temperature is a result of the average kinetic energy of all the atoms comprising the solid/liquid/gas. In solid, these atoms can just vibrate in place, leaving them to only be able to conduct and radiate heat. However, as you probably know liquids and solids take the shape of their container because the bonds between atoms are loose enough to allow them to freely move around. Due to each individual atom having its own energy, and these atoms being free to move about the liquid/gas they collide with other atoms in the substance. These collisions result in a transfer of energy. Finally, lower energy atoms "sink" and higher energy atoms "rise" thus creating a "convection current".
The formula for a kinetic energy KE of a falling body is
KE = mgh
where m = mass, g = acceleration due to gravity (9.8 m/s^2, constant), h = height.
The total mass of a skateboader and a skateboard is 64 + 2.0 = 66 kg.
Finally,
KE = 66*9.8*5.0 = 32340 J
D = 1/f, where D is the power in diopters and f is the focal length in meters.
D=1/20
<u>D=0.05</u>