Two children push on opposite sides of a door during play. Both push horizontally and perpendicular to the door. One child pushes with a force of 30 N at a distance of 60 cm from the hinges, and the second child pushes at a distance of 45 cm. Assume friction is negligible. The force must the second child exert to keep the door from moving is (A) 40 N (B) 30 N (C) 60 N (D) Cannot be determined

Select the best definition for wavelength. the height of an oscillating electromagnetic wave the rate at which electromagnetic waves oscillate. the distance between two crests of an electromagnetic wave. the oscillations of electric and magnetic fields select the best definition for frequency. the oscillations of electric and magnetic fields. the height of an oscillating electromagnetic wave. the distance between two crests of an electromagnetic wave. the rate at which electromagnetic waves oscillate