A projectile is fired at an angle such that the vertical component of its velocity and the horizontal component of its velocity are BOTH equal to 30 m/s.
a. Using the approximate value of g = +/-10 m/s2, how long in time does it take for the
ball to reach its high point?

It takes 3 seconds to reach its high point

Explanation:

Projectile Motion

In a projectile motion (or 2D motion), the object is launched with an initial angle θ and an initial velocity vo.

The components of the velocity are

The speed in the horizontal direction at any time t is:

The time taken to reach the maximum height is when vy=0, or:

We are given the y-component of the velocity, thus:

It takes 3 seconds to reach its high point

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.