Answer:
See explanations below
Explanation:
Power = Workdone/Time
Power of washer = 450watts
Time used to clean the clothes = 1hour = 3600secs
Energy used to clean a load of clothes in 1 hour of
washing = 450/3600
Energy used to clean a load of clothes in 1 hour of
washing = 0.125Joules
For drying;
Energy = 3000/1.5*3600
Energy = 3000/5400
Energy = 0.556Joules
Hence the energy in washing id 0.556Joules
Answer: 117.8 nm
Explanation:
Given,
Nonreflective coating refractive index : n = 1.21
Index of refraction: 
= 1.52
Wave length of light = λ = 570 nm = 
Hence, the minimum thickness of the coating that will accomplish= 117.8 nm
Answer:
a) 70 N, b) b. Each initially applied a force bigger than static friction to get the box moving and accelerating, then when the desired final speed was achieved they reduced the force to make the net force zero.
Explanation:
a) A constant speed means that magnitude of friction force is equal to the magnitude of the external force. The friction force is directly proportional to the normal force, which is equal to the weight of the box. Therefore, the magnitude of the force is 70 N.
b) Alice used initially a greater force to accelerate the box up to needed speed and later reduced the external force to keep speed constant. The right choice is option b.
Answer:
The Doppler shift may be helpful to determine the relative speed of an object by bouncing a wave (usually a radar wave) off the object and measuring the shift in the frequency of the wave.
Explanation:
Doppler shift helps to overcome a visual illusion block out irrelevant noises, locate sounds and see an object in very dim light by determining the relative speed of an object by bouncing a wave
Answer:
549.9 ohms, 65.65 watts, the power went up
Explanation: power P = V²/R
v= 190volts , P =62watts
from P =V²/R
62=190²/R
making R the subject
R×62= 190²
62R =36100
R=36100/62
R=586.25 ohms
Resistance of each lamp = 586.26/18 =32.3ohms
a) resistance of the light string now = 17×32.3 = 549.9 ohms
b) P=V²/R
where R=549.9ohms , P=?
P=190²/549.9
P=36100/549.9
P=65.65watts
Power dissipated has increased( went up )
