Jermaine and lashonda each rub their dry hair with inflated balloons. while doing this, the other students notice that their hair is starting to stick straight out. next, the teacher takes the balloons and places them right next to one another. however, the balloons will not stay next to each other, as they normally would. instead, they spring apart in opposite directions. what is causing these balloons to push each other away?

As you are trying to move a heavy box of mass m, you realize that it is too heavy for you to lift by yourself. there is no one around to , so you attach an ideal pulley to the box and a massless rope to the ceiling, which you wrap around the pulley. you pull up on the rope to lift the box. use g for the magnitude of the acceleration due to gravity and neglect friction forces. once you have pulled hard enough to start the box moving upward, what is the magnitude f of the upward force you must apply to the rope to start raising the box with constant velocity? express the magnitude of the force in terms of m, the mass of the box.

Arefrigerator uses r-134a as the working fluid and operates on the ideal vapor-compression refrigeration cycle except for the compression process. the refrigerant enters the evaporator at 120 kpa with a quality of 34 percent and leaves the compressor at 70°c. if the compressor consumes 450 w of power, determine (a) the mass flow rate of the refrigerant, (b) the condenser pressure, and (c) the cop of the refrigerator. (0.00644 kg/s, 800 kpa, 2.03)

Listed below are the measured radiation absorption rates (in w/kg) corresponding to 11 cell phones. use the given data to construct a boxplot and identify the 5-number summary. 1.16 0.85 0.69 0.75 0.95 0.93 1.18 1.17 1.42 0.54 0.57 the 5-number summary is nothing, nothing, nothing, nothing, and nothing, all in w/kg. (use ascending order. type integers or decimals. do not round.)