Answer:
Explanation:
The rate of conductive heat transfer in watts is:
q = (k/s) A ΔT
where k is the heat conductivity, s is the thickness, A is the area, and ΔT is the temperature difference.
a)
Given k = 52.4 W/m/K, s = 0.014 m, and ΔT = 350-140 = 210 K, we can find q/A:
q/A = (52.4 / 0.014) (210)
q/A = 786,000 W/m²
b)
Given that A = 0.42 m², we can find q:
q = (0.42 m²) (786,000 W/m²)
q = 330,120 W
A watt is a Joule per second. Convert to Joules per hour:
q = 330,120 J/s * 3600 s/hr
q = 1.19×10⁹ J/hr
c)
If we change k to 1.8 W/m/K:
q = (k/s) A ΔT
q = (1.8 / 0.014) (0.42) (210)
q = 11,340 J/s
q = 4.08×10⁷ J/hr
d)
If k is 52.4 W/m/K and s is 0.024 m:
q = (k/s) A ΔT
q = (52.4 / 0.024) (0.42) (210)
q = 192,570 J/s
q = 6.93×10⁸ J/hr
Answer:
Waves. Refraction is an effect that occurs when a light wave, incident at an angle away from the normal, passes a boundary from one medium into another in which there is a change in velocity of the light. ... The wavelength decreases as the light enters the medium and the light wave changes direction.
Explanation:
As a wavelength increases in size, its frequency and energy (E) decrease. From these equations you may realize that as the frequency increases, the wavelength gets shorter. ... Mechanical and electromagnetic waves with long wavelengths contain less energy than waves with short wavelengths.
This question is based on the fundamental assumption of vector direction.
A vector is a physical quantity which has magnitude as well direction for its complete specification.
The magnitude of a physical quantity is simply a numerical number .Hence it can not be negative.
A negative vector is a vector which comes into existence when it is opposite to our assumed direction with respect to any other vector. For instance, the vector is taken positive if it is along + X axis and negative if it is along - X axis.
As per the first option it is given that a vector is negative if its magnitude is greater than 1. It is not correct as magnitude play no role in it.
The second option tells that the magnitude of the vector is less than 1. Magnitude can not be negative. So this is also wrong.
Third one tells that a vector is negative if its displacement is along north. It does not give any detail information about the negativity of a vector.
In a general sense we assume that vertically downward motion is negative and vertically upward is positive. In case of a falling object the motion is vertically downward. So the velocity of that object is negative .
So last option is partially correct as the vector can be negative depending on our choice of co-ordinate system.
Answer:
C
Explanation:
- Let acceleration due to gravity @ massive planet be a = 30 m/s^2
- Let acceleration due to gravity @ earth be g = 30 m/s^2
Solution:
- The average time taken for the ball to cover a distance h from chin to ground with acceleration a on massive planet is:
t = v / a
t = v / 30
- The average time taken for the ball to cover a distance h from chin to ground with acceleration g on earth is:
t = v / g
t = v / 9.81
- Hence, we can see the average time taken by the ball on massive planet is less than that on earth to reach back to its initial position. Hence, option C
Answer:
, Nervous tissue is composed of two types of cells, neurons and glial cells. Neurons are the primary type of cell that most anyone associates with the nervous system. They are responsible for the computation and communication that the nervous system provides.
