A 72-kg man stands on a spring scale in an elevator. Startingfrom rest, the elevator ascends, attaining its maximum speed of 1.2m/s in 0.80 s. The elevator travels with this constant speed for5.0 s, undergoes a uniform negative acceleration for 1.5s, and then comes to rest. What does the spring scale register (a) before the elevator starts to Move?
(b) during the first 0.80 s ofthe elevator's ascent?
(c) while the elevator is traveling atconstant speed?
(d) during the elevator's negativeacceleration?

Which feature of a heating curve indicates a change ofn state

Athin plate moves between two parallel, horizontal, stationary flat surfaces at a constant velocity of v = 7.5 m/s. the two stationary surfaces are spaced 4 cm apart, and the medium between them is filled with oil whose viscosity is 0.9 n·s/m2. the part of the plate immersed in oil at any given time is 2 m long and 0.5 m wide. if the plate moves through the mid-plane between the surfaces, determine the force required to maintain this motion. what would your response be if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top surface (h1)? if the plate moves through the mid-plane between the surfaces, the force required to maintain the motion will be n. if the plate was 1 cm from the bottom surface (h2) and 3 cm from the top (h1) surface, the force required to maintain the motion would be n.

The focal length of a relaxed human eye is approximately 1.7 cm. when we focus our eyes on a close up object, we can change the refractive power of the eye by about 16 diopters. (a) does the refractive power of our eyes increase or decrease by 16 diopters when we focus closely? explain. (b) calculate the focal length of the eye when we focus closely.