A point charge (m = 2.0 g ) at the end of an insulating string of length 55 cm is observed to be in equilibrium in a uniform horizontal electric field of 9400 N/C , when the pendulum's position is as shown in (Figure 1), with the charge 12 cm above the lowest (vertical) position.

If the field points to the right in the figure, determine the magnitude of the point charge.

Express your answer to two significant figures and include the appropriate units.

Ablock of mass m = 2.5 kg is attached to a spring with spring constant k = 740 n/m. it is initially at rest on an inclined plane that is at an angle of theta= 26 with respect to the horizontal, and the coefficient of kinetic friction between the block and the plane is uk = 0.17. in the initial position, where the spring is compressed by a distance of d = 0.16 m, the mass is at its lowest position and the spring is compressed the maximum amount. take the initial gravitational energy of the block as zero. the block's initial mechanical energy is 9.472 j.b. if the spring pushes the block up the incline, what distance l in meters will the block travel before coming to rest? the spring remains attached to both the block and the fixed wall throughout its motion.