Afarsighted boy has a near point at 2.3 m and requires eyeglasses to correct his vision. corrective lenses are available in increments in power of 0.25 diopters. the eyeglasses should have lenses of the lowest power for which the near point is no further than 25 cm. the correct choice of lens power for eyeglasses, in diopters, is:

The 5-kg cylinder is initially at rest when it is placed in contact with the wall b and the rotor at a. if the rotor always maintains a constant clockwise angular velocity v = 6 rad> s, determine the initial angular acceleration of the cylinder. the coefficient of kinetic friction at the contacting surfaces b and c is mk = 0.2.

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.

Is there a point between a 10 nc charge and a 20 nc charge at which the electric field is zero?