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

Calculate the amount of heat produced when 18000 coulombs of charge is transferred in one hour through a potential difference of 50v

Atelevision set that has been running for a while heats up even the air around it. which two laws of thermodynamics could be used to analyze this scenario

Awater balloon launcher uses an elastic band with a spring constant of 115 n/m to use thee launcher you stretch thee band back with a balloon n it the water balloons have a mass of 1.3 kg a) if you stretch the band by 0.8 m, what elastic force will the band exert? b) with the band stretched 0.8 m, how much elastic potential energy is stored in the spring? c) if you release the band, it pushes forward. what is the kinetic energy of the balloon when it reaches the natural length of the band? d) what is the speed of the balloon when it reaches the natural length of the band?