Một vật chuyển động nhanh dần đều theo đường thẳng. Đánh dấu điểm A trên đường thẳng đó, đo quãng đường vật đi tiếp từ A, ta thấy: đoạn đường AB dài 9,9 m vật đi mất thời gian 3 giây, đoạn đường AC dài 17,5 m vật đi mất thời gian 5 giây. Xác định gia tốc của vật và thời gian từ lúc vật bắt đầu chuyển động đến khi vật tới A?

You are still fascinated by the process of inkjet printing, as described in the opening storyline for this chapter. you convince your father to take you to his manufacturing facility to see the machines that print expiration dates on eggs. you strike up a conversation with the technician operating the machine. he tells you that the ink drops are created using a piezoelectric crystal, acoustic waves, and the plateau-rayleigh instability, which creates uniform drops of mass m = 1.25 ✕ 10−8 g. while you don't understand the fancy words, you do recognize mass! the technician also tells you that the drops are charged to a controllable value of q and then projected vertically downward between parallel deflecting plates at a constant terminal speed of 20.0 m/s. the plates are ℓ = 2.15 cm long and have a uniform electric field of magnitude e = 6.40 ✕ 104 n/c between them. noting your interest in the process, the technician asks you, "if the position on the egg at which the drop is to be deposited requires that its deflection at the bottom end of the plates be 0.17 mm, what is the required charge on the drop (in c)? " you quickly get to work to find the answer. (neglect the force of gravity.)