Force f=2.0n i - 3.0n k acts on a pebble with position vectorr=0.50m j - 2.0m k relative to the origin. in unit vector notation, what is the resulting torque on the pebble about (a) the origin and(b) the point (2.0m, 0,-3.0m)? a) dot product of f*r=(-3..0m)=6.0nmb) sqrt( 2.0^2+0^2+3.0^2) = sqrt(13)i've tried but not sure. me. you.

Red light strikes a metal surface and electrons are ejected. if violet light is now used with a 10% greater intensity, what will happen to the ejection rate (number of ejected electrons per second) and the maximum energy of the electrons? a) greater ejection rate; same maximum energyb) same ejection rate; greater maximum energyc) greater ejection rate; greater maximum energyd) same ejection rate; same maximum energye) none of the above answers are correct

Electromagnetic induction. a coil of wire contains n turns and has an electrical resistance r. the radius of each turn is a. initially, inside the coil there exists a uniform magnetic field of magnitude b0 parallel to the axis of the coil. the magnetic field is then reduced slowly. the current induced in the coil is i. how long does it take for the magnitude of the uniform field to drop to zero?

Alarge box of mass m is pulled across a horizontal frictionless surface by a horizontal rope with tension t. a small box of mass m sits on top of the large box. the coefficients of static and