Answer:W = 1.23×10^-6BTU
Explanation: Work = Surface tension × (A1 - A2)
W= Surface tension × 3.142 ×(D1^2 - D2^2)
Where A1= Initial surface area
A2= final surface area
Given:
D1=0.5 inches , D2= 3 inches
D1= 0.5 × (1ft/12inches)
D1= 0.0417 ft
D2= 3 ×(1ft/12inches)
D2= 0.25ft
Surface tension = 0.005lb ft^-1
W = [(0.25)^2 - (0.0417)^2]
W = 954 ×10^6lbf ft × ( 1BTU/778lbf ft)
W = 1.23×10^-6BTU
Answer:
(a) 1320 W
(b) 480 W
(c) E':E ≈ 11:2
Explanation:
(a) Applying,
P' = VI'................. Equation 1
Where P' = Power of the blow-dryer, V = Voltage, I = current rating of the blow-dryer.
From the question,
Given: V = 120 V, I' = 11 A
Substitute these values into equation 1
P = (120×11)
P = 1320 W
(b) Similarly,
P = VI................... Equation 2
Where P = Power of the vacuum cleaner. I = current rating of the vacuum cleaner.
Also Given: I = 4 A,
Therefore
P = 4(120)
P = 480 W
(c)
E' = P'/t'............. Equation 3
E = P/t................ Equation 4
Where E' = Energy of the blow-dryer, t' = time of use of the blow-dryer, E = Energy of the vacuum cleaner, t = time of use of the vacuum cleaner
From the question,
Given: t' = 15 minutes = (15×60) = 900 seconds, t = 30 minutes = (30×60) = 1800 seconds
Substitute these values into equation 3 and 4
E' = 1320/900
E' = 1.47 J,
E = 480/1800
E = 0.267
Therefore,
E':E = 1.47:0.267
E':E ≈ 11:2
Answer:
B. A car sits at rest at a stop sign.
Answer:19.5 m
Explanation:
Given
coefficient of kinetic Friction 
Initial speed 
Friction is present so it tries to stop to the object and stops it completely after moving certain distance let say s
maximum deceleration provided by friction is
using equation of motion
where 
Answer:
Chemical elements, a dense lustrous yellow precious metal of group.
