Five principles for research ethics
Discuss intellectual property frankly
Be conscious of multiple roles
Follow informed-consent rules.
Respect confidentiality and privacy.
Tap into ethics resources.
Answer:
2m₁m₃g / (m₁ + m₂ + m₃)
Explanation:
I assume the figure is the one included in my answer.
Draw a free body diagram for each mass.
m₁ has a force T₁ up and m₁g down.
m₂ has a force T₁ up, T₂ down, and m₂g down.
m₃ has a force T₂ up and m₃g down.
Assume that m₁ accelerates up and m₂ and m₃ accelerate down.
Sum of the forces on m₁:
∑F = ma
T₁ − m₁g = m₁a
T₁ = m₁g + m₁a
Sum of the forces on m₂:
∑F = ma
T₁ − T₂ − m₂g = m₂(-a)
T₁ − T₂ − m₂g = -m₂a
(m₁g + m₁a) − T₂ − m₂g = -m₂a
m₁g + m₁a + m₂a − m₂g = T₂
(m₁ − m₂)g + (m₁ + m₂)a = T₂
Sum of the forces on m₃:
∑F = ma
T₂ − m₃g = m₃(-a)
T₂ − m₃g = -m₃a
a = g − (T₂ / m₃)
Substitute:
(m₁ − m₂)g + (m₁ + m₂) (g − (T₂ / m₃)) = T₂
(m₁ − m₂)g + (m₁ + m₂)g − ((m₁ + m₂) / m₃) T₂ = T₂
(m₁ − m₂)g + (m₁ + m₂)g = ((m₁ + m₂ + m₃) / m₃) T₂
m₁g − m₂g + m₁g + m₂g = ((m₁ + m₂ + m₃) / m₃) T₂
2m₁g = ((m₁ + m₂ + m₃) / m₃) T₂
T₂ = 2m₁m₃g / (m₁ + m₂ + m₃)
42.9°
Explanation:
Let's assume that the x-axis is aligned with the incline and the positive direction is up the incline. We can then apply Newton's 2nd law as follows:
Note that the net force is zero because the block is moving with a constant speed when the angle of the incline is set at Solving for the angle, we get
or
Explanation:
The runner runs for a total time of
\Delta t=10.0 min= 600 sΔt=10.0min=600s
The energy converted by the runner during this time is equal to the power of the runner times the total time:
E=P \Delta t=400 W \cdot 600 s =2.4 \cdot 10^5 JE=PΔt=400W⋅600s=2.4⋅10
5
J
The photoelectric effect is obtained when you shine a light on a material, resulting in the emission of electrons.
The kinetic energy of the electrons depends on the frequency of the light:
K = h(f - f₀)
where:
K = kinetic energy
h = Planck constant
f = light frequency
f₀ = threshold frequency
Rearranging the formula in the form y = m·x + b, we get:
K = hf - hf₀
where:
K = dependent variable
f = <span>indipendent variable
h = slope
hf</span>₀ = y-intercept
Every material has its own threshold frequency, therefore, what stays constant for all the materials is h = Planck constant (see picture attached).
Hence, the correct answer is
C) the slope.