We can base this on the equation of thermal expansion.
ΔL = L₀αΔT
where
ΔL is the expansion of length upon heating
L₀ is the initial length
α is the coefficient of linear expansion
ΔT is the temperature difference
So, if α for Aluminum is greater than α for Copper, then after heating, aluminum would be longer than copper.
A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.
Answer: A. at the point which
is twice the focal lenght of the lens of the camera
Explanation:
When a certain document is to be produced through the use of a duplicating camera, it should be noted that the camera should be placed at the point which is twice the focal lenght of the lens of the camera so as to get the exact copy of the document.
It should be noted that placing the camera between the principal and a point twice the focal lens of the camera lens or beyond a point that's twice the focal length will not produce the document.
Therefore, the correct option is A
Answer: 2.86 m
Explanation:
To solve this question, we will use the law of conservation of kinetic and potential energy, which is given by the equation,
ΔPE(i) + ΔKE(i) = ΔPE(f) + ΔKE(f)
In this question, it is safe to say there is no kinetic energy in the initial state, and neither is there potential energy in the end, so we have
mgh + 0 = 0 + KE(f)
To calculate the final kinetic energy, we must consider the energy contributed by the Inertia, so that we then have
mgh = 1/2mv² + 1/2Iw²
To get the inertia of the bodies, we use the formula
I = [m(R1² + R2²) / 2]
I = [2(0.2² + 0.1²) / 2]
I = 0.04 + 0.01
I = 0.05 kgm²
Also, the angular velocity is given by
w = v / R2
w = 4 / (1/5)
w = 20 rad/s
If we then substitute these values in the equation we have,
0.5 * 9.8 * h = (1/2 * 0.5 * 4²) + (1/2 * 0.05 * 20²)
4.9h = 4 + 10
4.9h = 14
h = 14 / 4.9
h = 2.86 m