#!/usr/bin/env python
# coding: utf-8

# # Utilities module usage

# In[ ]:


from rocketpy.utilities import (
    calculate_equilibrium_altitude,
    compute_cd_s_from_drop_test,
)


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get_ipython().run_line_magic('matplotlib', 'widget')


# ### 1. Estimations for your cd_s

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compute_cd_s_from_drop_test(
    terminal_velocity=10,  # The desired terminal velocity (m/s)
    rocket_mass=20,  # kg
    air_density=1.225,
    g=9.80665,
)


# ### 2. Altitude of Terminal Velocity being reached 

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a, b, c = calculate_equilibrium_altitude(
    rocket_mass=20,
    cd_s=5,
    z0=1000,
    v0=-20,
    env=None,
    eps=1e-3,
    max_step=0.1,
    see_graphs=True,
    g=9.80665,
    estimated_final_time=10,
)

altitude_function, velocity_function, final_sol = a, b, c


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final_sol


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print(
    f"The terminal velocity of {final_sol['velocity']:.3} m/s is reached after {final_sol['time']:.3} seconds at altitude of {final_sol['altitude']:.6} meters."
)