Asingle-square threaded 35-mm power screw is 35 mm in diameter with a pitch of 5 mm. a vertical load on the screw reaches a maximum of 5 kn. the coefficients of friction are 0.06 for the collar and 0.09 for the threads. the frictional diameter of the collar is 45 mm. find the overall efficiency and the torque to "raise" and "lower" the load. repeat this problem if acme screw is used in this design.

If a particle moves along a path such that r : (3 sin t) m and ? : 2t rad, where t is in seconds. what is the particle's acceleration in m/s in 4 seconds? a)- 16.43 b)- 16.29 c)- 15.21 d)- 13.79

Consider a large isothermal enclosure that is maintained at a uniform temperature of 2000 k. calculate the emissive power of the radiation that emerges from a small aperture on the enclosure surface. what is the wavelength ? , below which 10% of the emission is concentrated? what is the wavelength ? 2 above which 10% of the emission is concentrated? determine the wavelength at which maximum spectral emissive power occurs. what is the irradiation incident on a small object placed inside the enclosure?

Shafts are machine elements that are used to a) carry axial loads b) direct shear loads c) transmit power d) rotate at constant speed e) none of the above circular and square shafts subjected to the same torque under the same circum behave a) the same way b) almost the same way