The answer to that will be the Troposphere.
A) 
Let's start by writing the equation of the forces along the directions parallel and perpendicular to the incline:
Parallel:
(1)
where
m is the mass
g = 9.8 m/s^2 the acceleration of gravity

is the coefficient of friction
R is the normal reaction
a is the acceleration
Perpendicular:
(2)
From (2) we find

And substituting into (1)

Solving for a,

B) 5.94 m/s
We can solve this part by using the suvat equation

where
v is the final velocity
u is the initial velocity
a is the acceleration
s is the displacement
Here we have
v = ?
u = 0 (it starts from rest)

s = 8.70 m
Solving for v,

Any change in the speed or direction of motion is called "acceleration". You'll hear "deceleration" used for slowing down but that's not technically correct.
Responder:
- Volumen del bloque = 60cm³
- Densidad = 5g / cm³
Explicación:
Dada la dimensión del bloque
AB = 4 cm, BC = 2.5 cm y BF = 6 cm
Volumen del bloque = Largo × Ancho × Alto
Volumen del bloque = AB × BC × BF
Volumen del bloque = 4 × 2.5 × 6
Volumen del bloque = 60cm³
Dada la masa del bloque = 300 gramos
Densidad = Masa / Volumen
Densidad = 300g / 60cm³
Densidad = 5g / cm³
Algunos materiales que tienen una densidad de 5g / cm³ o cercanos son radio, germanio y europio con densidades de 5g / cm³, 5.3g / cm³ y 5.24g / cm³ respectivamente.