With respect to the earth, object 1 is moving at speed 0.90 c to ...

[DyllonKazuo]

With respect to the earth, object 1 is moving at speed 0.90 c to the right. Object 2 is moving to the left at speed 0.70 c with respect to object 1. How fast is object 2 moving with respect to the earth?
 
  A)
 
  0.12 c
  B)
 
  -0.20 c
  C)
 
  0.54 c
  D)
 
  0.20 c
  E)
 
  1.6 c

Question 2

An object of mass 4 kg starts at rest from the top of a rough inclined plane of height 10 m as shown in Fig. 8-9.
 
  If the speed of the object at the bottom of the inclined plane is 10 m/s, how much work is done by the force of friction? Use g = 10 m/s2. A)
 
  -100 J
 
  B)
 
  100 J
 
  C)
 
  0
 
  D)
 
  -200 J
 
  E)
 
  200 J

[kilada]

Answer to Question 1

C

Answer to Question 2

D

[DyllonKazuo]

Gracias!

[Liamb2179]

Excellent