A) We want to find the work function of the potassium. Apply this equation:
E = 1243/λ - Φ
E = energy of photoelectron, λ = incoming light wavelength, Φ = potassium work function
Given values:
E = 2.93eV, λ = 240nm
Plug in and solve for Φ:
2.93 = 1243/240 - Φ
Φ = 2.25eV
B) We want to find the threshold wavelength, i.e. find the wavelength such that the energy E of the photoelectrons is 0eV. Plug in E = 0eV and Φ = 2.25eV and solve for the threshold wavelength λ:
E = 1243/λ - Φ
0 = 1243/λ - Φ
0 = 1243/λ - 2.25
λ = 552nm
C) We want to find the frequency associated with the threshold wavelength. Apply this equation:
c = fλ
c = speed of light in a vacuum, f = frequency, λ = wavelength
Given values:
c = 3×10⁸m/s, λ = 5.52×10⁻⁷m
Plug in and solve for f:
3×10⁸ = f(5.52×10⁻⁷)
f = 5.43×10¹⁴Hz
Doing a force balance on the car:
ma = Fr
ma = μmg
a = μg
a = 0.3(9.81)
a = 29.43 m/s2
Using the formula:
2ax = v2
2(29.43)(34) = v2
v = 44.74 m/s = 161.05 km/h
The car was going 44.74 m/s or 161.05 kph when the brakes were applied.
To solve this problem we will apply the concepts related to the Force of gravity from Newtonian theory for which it is necessary to

Where,
G = Gravitational universal constant
M = Mass of Earth
m = mass of Object
x = Distance between center of mass of the objects.
From this equation we can observe that the Force is inversely proportional to the squared distance between the two objects. The greater the distance, the lower the force of gravity and vice versa.

If you want to increase the force of gravity, you need to reduce the distance of the two. Therefore the correct option is B. Talk to the distance between them.
True because when the light bounces off a surface it creates a rainbow which we call roygbiv
Answer:
-5.6m/s²
Explanation:
Given parameters:
Initial speed = 11.2m/s
Time of running = 2s
Unknown:
Acceleration of the puppy = ?
Solution:
Acceleration is the rate of change of velocity with time.
So;
Acceleration =
final speed = 0m/s
Acceleration =
= -5.6m/s²