4. A block system is shown in figure. Frictional force on 2kg is f1 and on 3kg is f2 and T is tension in the string connecting block A and B. Which of the following statement is correct? (A) f1= 8i, f2 = -15icap, t=2n
(B)f1=-8icap, f2=-15icap, t=2n
(c)f1=5icap, f2=-15icap, t=5n
(d)f1=-5icap, f2=-15icap, t=5n

Apotter's wheel moves uniformly from rest to an angular speed of 0.20 rev/s in 32.0 s. (a) find its angular acceleration in radians per second per second. rad/s2 (b) would doubling the angular acceleration during the given period have doubled final angular speed?

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina. with the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 2.05cm in front of the eye.)

Agirl throws a ball. if the ball's acceleration is 12 m/sec/sec and its mass is 0.5 kg, how much force did the girl apply to the ball?