In the adjacent figure, the four particles form a square of edge length a= 5.00 cm and have charges q1 = -10nC , q2 = +20nC , q3 = -20nC , q4 = +10 nC. In unit-vector notation, what net electric field do the particles produce at the square's center?

Aman pushes on a trunk with a force of 250 newtons. the trunk does not move. how much positive work is done on the trunk? 0.0 j -250 j 250 j 125 j

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

What do you think car designers do if the damage caused by a crash test is too severe?