A sphere is constructed of two concentric parts. The inner part ...

[laurencescou]

A sphere is constructed of two concentric parts. The inner part is a solid sphere of radius 10.0 cm made of a material with density 4000 kg/m3. The outer part is a spherical shell with inner radius 10.0 cm and outer radius 20.0 cm.
 
  The material in the outer shell has a density 9000 kg/m3.
  (a) What is the mass of the sphere?
  (b) What is the average density of this sphere?

Question 2

Three cars, car X, car Y, and car Z, begin accelerating from rest, at the same time. Car X is more massive than car Y, which is more massive than car Z. The net force exerted on each car is identical.
 
  After 10 seconds, which car has the most amount of momentum? A) They all have the same amount of momentum
  B) Car X
  C) Car Y
  D) Car Z

[ky860224]

Answer to Question 1

(a) 281 kg (b) 8.38  103 kg/m3

Answer to Question 2

A

[laurencescou]

Thank you!

[ky860224]

Always glad to help...