You kick a soccer ball with a speed of 12 m/s at an angle of 21. how long does it take the ball to reach the top of its trajectory?

2.42 seconds

Explanation:

Assume that air resistance is negligible, use trigonometry to find the vertical component of the velocity by using trigonometry:

31⋅sin50=23.7

Where 31 ms−1 is the hypotenuse and by using sin to get the opposite component (vertical velocity) of the trajectory.

Now comes the use of the formula:
v = u + at
where v is the final velocity (0 ms−1), u is the initial velocity (31 ms−1 ), a is the acceleration of gravity (9.81 ms−2) and t is the time it takes to arrive at the top of the trajectory.

By making t as the subject:

t=v−ua

You can calculate the value of t:

0−23.7−9.81=2.42 (to 3 significant figures)

Better way to see it:

0−(31⋅sin50)−9.81=2.421 (to 4 significant figures)

Note: You must remember that you are dealing with velocity, not speed . Since velocity is a vector quantity, you must select the direction at which values will be positive. In my example, I set my upward direction as the positive value while my downward vectors as negative value (a, acceleration, 9.81 ms−1).

Which principle states: "geologic processes taking place on earth today operated similarly in the past and can be used to explain past geologic events"? a. lateral continuity

When is this