# No Idea How to Start

1. Sep 2, 2012

### creativeone

A cannon barrel is elevated at an angle of 45°. It fires a ball with a speed of 283 m/s. (For the following questions, ignore air resistance.)

(a) What height does the ball reach?
(b) How long is the ball in the air?
(c) What is the horizontal range of the cannon?

Known 2D kinematics equations

No idea how to start. Help me!

2. Sep 2, 2012

### Bhumble

I think after doing the other two problems you will have a better understanding of how to do this one.
Let me know if you still need help with this one after.
Hint:
$v_{x0} = v_0 cos( \theta )$
$v_{y0} = v_0 sin( \theta )$

3. Sep 2, 2012

### Delphi51

In grade 11 we do all these 2D motion problems by writing two headings: horizontal and vertical. Then write the formulas you have for the constant speed motion horizontally and the accelerated motion you have vertically. Next, put the known numbers in every formula. Hopefully one of the 3 or 4 formulas can be solved to find something. Finding the time of flight would be really nice because it applies to both the horizontal and vertical parts.