How fast would a rocket ship have to move to contract to half of ...

[beccaep]

How fast would a rocket ship have to move to contract to half of its proper length (as observed by a stationary object)?
 
  A)
 
  0.25c
  B)
 
  0.50c
  C)
 
  0.65c
  D)
 
  0.78c
  E)
 
  0.87c

Question 2

A ball is thrown straight up with a speed of 30 m/s.
 
  (a.) How long does it take the ball to reach the maximum height?
  (b.) What is the maximum height reached by the ball?
  (c.) What is its speed after 4.2 s?

[cassie_ragen]

Answer to Question 1

E

Answer to Question 2

(a.) 3.1 s
(b.) 46 m
(c.) 11 m/s

[beccaep]

Thank you!

[cassie_ragen]

Always glad to help...