Answer:
\alpha = \frac{2F}{3m} \ \frac{1}{r}
maximmun x =r
Explanation:
In this exercise we are asked for the maximum angular acceleration, let's start by writing the second law of / newton for rotational motion. Let's fix our reference system at the midpoint of the bar that has a length 2r
Σ τ = (I₁ + I₂) α
where I₁ and I₂ moment of inertia of the capsule with masses m and 2m, respectively. Let's treat these capsules as point particles
I₁ = m r²
I₂ = 2m r²
the troque of a pair of force is the force times the distance perpendicular to the point of application of the force which is the same for both forces, we will assume that the counterclockwise rotation is positive
Στ = F x + F x
the angular acceleration is the same because they are joined by the bar of negligible mass, let us substitute
2 F x = (m r² + 2m r²) α
α =
α =
let's analyze this expression
* for the application point in the center (x = 0) at acceleration is zero
* for the point of application of the torque at the ends the acceleration is
this being its maximum value
Answer:
(a) silver
(b) 4.94 x 10^-8 ohm
Explanation:
L = 2.4 m
diameter = 5.99 mm = 5.99 x 10^-3 m
Radius, r = diameter / 2 = 2.995 x 10^-3 m
R = 1.38 x 10^-3 ohm
(a) Let ρ be the resistivity of the material
R = ρ L / A
R A / L = ρ
ρ = (1.38 x 10^-3 x 3.14 x 2.995 x 10^-3 x 2.995 x 10^-3) / 2.4
ρ = 1.62 x 10^-8 ohm-m
The material is silver.
(b) t = 1.2 mm = 1.2 x 10^-3 m
Diameter = 2.24 cm = 0.0224 m
Radius, r = 0.0112 m
Resistance, R = ρ x t / A
R = 1.62 x 10^-8 x 1.2 x 10^-3 / (3.14 x 0.0112 x 0.0112)
R = 4.94 x 10^-8 ohm
Answer:
1. The frequency of the incident light must be equal to or greater than the threshold frequency of the photons before emission could take place.
2. The intensity of the incident light is proportional to the amount of photons released. The higher the intensity of light, the greater the amount of photons ejected.
Explanation:
1. Photoelectric effect is the process by which light with sufficient frequency falls on the surface of a material, e.g metal, to emit electrons. The incident light must have a minimum value of required frequency for the electrons to be ejected. This energy is termed work function which is a function of frequency.
So for emission to take place, the frequency of the incident light must be equal to or greater than the threshold frequency of the photons.
2. The intensity of light is a measure of the amount of light per unit area. When the intensity of incident light increases, the probability that photons would be released increases. The intensity of the incident light is proportional to the amount of photons released.
The surface is frictionless, so there is no frictional force acting on the ball. There are no other forces acting on the ball in the horizontal direction, so it's a uniform motion with constant speed. Therefore, the velocity of the ball will remain the same for the entire duration of the motion, and so after 5 seconds the velocity is still 15 m/s.
I think it’s the lunar eclipse
Hope that is right