Answer:
a. 3 s.
Explanation:
Given;
angular acceleration of the wheel, α = 4 rad/s²
time of wheel rotation, t = 4 s
angle of rotation, θ = 80 radians
Apply the kinematic equation below,

Given initial angular velocity, ω₀ = 0
Apply the kinematic equation below;

Therefore, the wheel had been in motion for 3 seconds.
a. 3 s.
Answer:
(a) 
(b) 
(c) 
Explanation:
The Planck-Einstein relation allows us to know the energy (E) of a photon, knowing its frequency (f). According to this relation, the energy of the photon is defined as:

Here h is the Planck constant.
(a)

(b)

(c)

Answer:
All the planets have nearly circular orbit except the Pluto
Explanation:
Planets closer to the Sun move around their orbits at a very high speed than planets farther from the Sun.
All the planets except Pluto, orbit the Sun in nearly the same plane.
All the planets have nearly circular orbits except Pluto because of it's distance from the sun which is over 5,000,000,000km
Its mass
As since gravitation potential energy = (MGH), which is basically (mass x acceleration due to gravity x height)
Answer:
The 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.
Explanation:
Area of 8 meter telescope

Area of 2 meter telescope

Dividing the equations we get

Hence, the 8-meter telescope has 16 times the light-collecting area of the 2-meter telescope.