Relative motion with cart and ball

[ryan1180]

Homework Statement

A cart moves with velocity vC = 10 m/s in the horizontal direction as shown below.

[PLAIN]https://online-s.physics.uiuc.edu/cgi/courses/shell/common/showme.pl?courses/phys100/fall10/hwb/04/01/cart.gif

A ball is ejected from the cart with an initial velocity vB with respect to the cart such that an observer on the ground sees the ball move directly vertical. The ball reaches its maximum height at a time t = 2 s after it is launched. The next two questions pertain to this situation.

1) The angle θ (as measured by someone on the cart) is greater than 90 degrees.

(True or False)

2) What is vB, the magnitude of the initial velocity of the ball with respect to the cart?

vB = 10 m/s
vB = 18 m/s
vB = 22 m/s
vB = 26 m/s
vB = 30 m/s
(multiple choice)

Homework Equations

vB=vBC+vCG

The Attempt at a Solution

I'm pretty sure that the answer to part 1 is false

For part 2 I think the answer is 10, but I get confused with relative motion...

 

[ryan1180]

Am I at least using the correct formula for this? I'm not even sure about that...