Q5.77: a hot-air balloon of mass 650 kg is descending vertically with downward acceleration of magnitude 2.75 m/s 2. how much mass (ballast) must be thrown out to give the balloon an upward acceleration of magnitude 2.75 m/s 2? assume that the upward force from the air (the lift) does not change because of the decrease in mass.

Which statement best describes the superposition principle? a.) if two in-phase waves arrive simultaneously at a point, their amplitudes add up b.) if two out-of-phase waves arrive simultaneously at a point, their amplitudes add up c.) if two in-phase waves arrive at a point one after another, their amplitudes add up d.) if two out-of-phase waves arrive at a point one after another, their amplitudes adds up

Against his financial advisor's advice, frank has decided to invest his money in some risky stocks because he once made quite a bit of money in the stock market. his decision illustrates a. the representativeness heuristic b. overconfidence c. the availability heuristic d. confirmation bias select the best answer from the choices provided

Why should the wavelength scale of spectroscope be calibrated