Trên trục Ox, cho hai chất điểm dao động điều hòa cùng phương có phương trình li độ lần lượt là x1= A1cos10t(cm); x2=A2cos(10t + j) cm. Biết rằng 400+ 225= 144 (cm2). a. Xác định biên độ dao động tổng hợp của hai dao động trênA. 1 cmB. 0,6 cmC. 0,8 cmD. 0,2 cm

Julia would be observing a. static electricity was caused by her sweater rubbing against her shirt and transferring electrons. she didn't touch anything metal, so that would cancel out b.she most likely didn't rub her sweater against her hair either, so that cancels out c.she also didn't scoot across the carpet while trying to take her sweater off, that cancels out d.so that leaves a.a. is correct.

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j