Answer metalloids hope this helps
Answer:
A. Air
Explanation:
A thermal insulator is a material that does not let the heat trasmitting through it, or it transmits heat not very efficiently.
Generally, the lower the density of the material, the better insulator the material is: this is because in materials with very low density, particles are very spread apart, so they cannot collide with each other, and so the vibrations of the particles (which determine how hot a substance is) cannot be transmitted very efficiently.
In the options listed in this problem, air is the material with lowest density, therefore it is the best thermal insulator among them.
E = hf = hc/λ
= (6.6 x 10^-34) × (3 × 10^8) ÷ (3.1 × 10^-7)
=6.138 × 10^-32 J
With that information you can only suppose a uniformly accelerated motion. This is, acceleration is constant.
Then, acceleration = change in velocity / change in time = (58 -54)km/h / 2 h = 4km/h / 2 h = 2 km/h^2
Then the equation for velocity, V is
V = Vo + a*t = Vo + 2 (km/h^2) * t = Vo + 2t
Vo is the initial velocity, which you can find using V = 54km/h and t = -2
Vo = V after 2 hours - a*(2hours) = 54km/h - 2(km/h^2)*2h = 54km/k - 4km/h = 50km/h
Then, the equation is: V = 50 km/h + 2t
Valid for constant acceleration.
A :-) for this question , we should apply
a = v - u by t
Given - u = 4.77 m/s
v = 23.5 m/s
t = 5.18 m/s
Solution -
a = v - u by t
a = 23.5 - 4.77
a = 28.27 m/s^2
.:. The acceleration is 28.27 m/s^2
