A mass of 2 Kg is attached to a spring on a horizontal frictionless surface. It is observed that the spring exerts a (81/50) N force when stretched by (1/100) metres. Apart from the spring force and the damping force there no other external forces on the mass. In two separate experiments A and B it is attached to two different viscous dampers. A) A viscous damper that exerts a damping force of (27/100) N when the mass is moving at (1/100) ms^{-1}. B) A viscous damper that exerts a damping force of (9/20) N when the mass is moving at (1/100) ms^{-1}.

The softest and hardest minerals are: softest hardest

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

The dipole moment of the water molecule (h2o) is 6.17x10^-30 c.m. consider a water molecule located at the origin whose dipole moment p points in the +x-direction. a chlorine ion ( of charge-1.60x10^-19c , is located at x=3.00x10^-9m . assume that is much larger than the separation d between the charges in the dipole, so that the approximate expression for the electric field along the dipole axis can be used. a) find the magnitude of the electric force that the water molecule exerts on the chlorine ion. b) what is the direction of the electric force. -x-direction or +x-direction c) is this force attractive or repulsive?