Vectors/Projectileshelp please

[biglank3]

this is vectors and projectiles...our teacher told us how to do it...and i did exactly what he told us to do, but it isn't right...

A rocket is launched at an angle of 53° above the horizontal with an initial speed of 75 m/s, as shown in Figure 3-31. It moves for 21 s along its initial line of motion with an acceleration of 21 m/s2. At this time its engines fail and the rocket proceeds to move as a free body.

(a) What is the rocket's maximum altitude?

(b) What is the rocket's total time of flight?

(c) What is the rocket's horizontal range?

 

[Mattowander]

What work have you done?

 

[baba89]

I can understand your frustration with not getting the correct answer despite following your teacher's instructions. It's important to remember that science, especially physics, is all about problem-solving and understanding the principles behind the equations and calculations. It's possible that there may have been a mistake in your calculations or a misunderstanding of the concept.

To solve this problem, we need to use the equations of motion for projectiles. The key is to break down the initial motion of the rocket into two parts: the motion with the engines on and the motion as a free body after the engines fail.

For part (a), we can use the equation h = h0 + v0yt - 0.5gt^2 to find the maximum altitude, where h0 is the initial height, v0y is the initial vertical velocity, g is the acceleration due to gravity, and t is the time. We know that at the maximum altitude, the vertical velocity will be 0. So, we can set v0y = 75sin(53°) and solve for t. Then, plug in the values to find the maximum altitude.

For part (b), we can use the equation v = v0 + at to find the time it takes for the rocket to reach its maximum altitude, where v0 is the initial velocity, a is the acceleration, and t is the time. We know that at the maximum altitude, the vertical velocity is 0, so we can set v0 = 75sin(53°) and solve for t. Then, we can add this time to the initial time of 21 seconds to find the total time of flight.

For part (c), we can use the equation x = x0 + v0xt + 0.5at^2 to find the horizontal range, where x0 is the initial horizontal position, v0x is the initial horizontal velocity, a is the acceleration, and t is the time. We know that the initial horizontal velocity is 75cos(53°), and the final horizontal velocity is also 75cos(53°) since there is no horizontal acceleration. We can find the time it takes for the rocket to reach its maximum altitude, and then use that time to find the horizontal range.

I hope this helps you understand the problem better and find the correct answers. Remember to always double check your calculations and ask for help if you are still struggling. Keep practicing and you will get the hang of it