<span>3.92 m/s^2
Assuming that the local gravitational acceleration is 9.8 m/s^2, then the maximum acceleration that the truck can have is the coefficient of static friction multiplied by the local gravitational acceleration, so
0.4 * 9.8 m/s^2 = 3.92 m/s^2
If you want the more complicated answer, the normal force that the crate exerts is it's mass times the local gravitational acceleration, so
20.0 kg * 9.8 m/s^2 = 196 kg*m/s^2 = 196 N
Multiply by the coefficient of static friction, giving
196 N * 0.4 = 78.4 N
So we need to apply 78.4 N of force to start the crate moving. Let's divide by the crate's mass
78.4 N / 20.0 kg
= 78.4 kg*m/s^2 / 20.0 kg
= 3.92 m/s^2
And you get the same result.</span>
Rubber is a insulator so current cannot pass through it where as metal is a conductor which allows current to pass through it
Answer:
The lenses with different focal length are four.
Explanation:
Given that,
Radius of curvature R₁= 4
Radius of curvature R₂ = 8
We know ,
Refractive index of glass = 1.6
When, R₁= 4, R₂ = 8
We need to calculate the focal length of the lens
Using formula of focal length
Put the value into the formula
When , R₁= -4, R₂ = 8
Put the value into the formula
When , R₁= 4, R₂ = -8
Put the value into the formula
When , R₁= -4, R₂ = -8
Put the value into the formula
Hence, The lenses with different focal length are four.
Explanation:
Let 
is the mass of proton. It is moving in a circular path perpendicular to a magnetic field of magnitude B.
The magnetic force is balanced by the centripetal force acting on the proton as :
r is the radius of path,
Time period is given by :
Frequency of proton is given by :
The wavelength of radiation is given by :
So, the wavelength of radiation produced by a proton is 
. Hence, this is the required solution.
Answer: C. Some of uranium's mass is converted into energy, so the smaller atoms have less mass.
Explanation:
From Einstein's mass-energy relation:
E = mc²
Mass and energy are equivalent. Mass can be converted into energy and energy into mass.
When Uranium atoms under go nuclear fission, smaller atoms are formed and huge amount of energy is released. This energy comes from the mass difference of the uranium nuclei and new nuclei formed. This mass converted into energy according to Einstein's equation.
