Answer:
a) 49.95 watts
b) The self locking condition is satisfied
Explanation:
Given data
weight of the square-thread power screw ( w ) = 100 kg = 1000 N
diameter (d) = 20 mm ,
pitch (p) = 2 mm
friction coefficient of steel parts ( f ) = 0.1
Gravity constant ( g ) = 10 N/kg
Rotation of electric power screwdrivers = 300 rpm
A ) Determine the power needed to raise to the basket board
first we have to calculate T
T = Wtan (∝ + Ф ) * 
------------- equation 1
Dm = d - 0.5 ( 2) = 19mm
Tan ∝ = 
where L = 2*2 = 4
hence ∝ = 3.83⁰
given f = 0.1 , Tan Ф = 0.1. hence Ф = 5.71⁰
insert all the values into equation 1
T = 1.59 Nm
Determine the power needed using this equation
= 
= 49.95 watts
B) checking if the self-locking condition of the power screw is satisfied
Ф > ∝ hence it is self locking condition is satisfied
Answer:
<u>Option-(A)</u>
Explanation:
<u>Typical applications for the high carbon steels includes the following;</u>
It is heat treatable, relatively large combinations of mechanical characteristics. Typical applications: railway wheels and tracks, gears, crankshafts, and machine parts.
Answer:
Q = 63,827.5 W
Explanation:
Given:-
- The dimensions of plate A = ( 10 mm x 1 m )
- The fluid comes at T_sat , 1 atm.
- The surface temperature, T_s = 75°C
Find:-
Determine the total condensation rate of water vapor onto the front surface of a vertical plate
Solution:-
- Assuming drop-wise condensation the heat transfer coefficient for water is given by Griffith's empirical relation for T_sat = 100°C.
h = 255,310 W /m^2.K
- The rate of condensation (Q) is given by Newton's cooling law:
Q = h*As*( T_sat - Ts )
Q = (255,310)*( 0.01*1)*( 100 - 75 )
Q = 63,827.5 W
