Abunai Hana is standing atop a hill and fires her crossbow perfectly horizontally. If the crossbow bolt begins

moving with a speed of 35 m/s, then at what height does the bolt land if it hits the ground 150 m horizontally

away from her?

Respuesta :

Answer:

h = 90.09 m

Explanation:

First, we consider the horizontal motion of the crossbow. Considering air friction to be negligible we can use the following equation:

[tex]X = V_{x}t[/tex]

where,

X = horizontal distance covered = 150 m

Vₓ = Horizontal component of velocity = 35 m/s

t = time taken during the motion = ?

Therefore,

[tex]150\ m = (35\ m/s)t\\\\t = \frac{150\ m}{35\ m/s}\\\\t = 4.28\ s[/tex]

Now, we consider the vertical motion of the crossbow. Using second equation of motion:

[tex]h = V_{i}t + \frac{1}{2}gt^{2}\\\\[/tex]

where,

h = the height the bolt fell = ?

Vi = Vertical component of initial velocity = 0 m/s (since the crossbow was fired horizontally)

g = acceleration due to gravity = 9.81 m/s²

Therefore,

[tex]h = (0\ m/s)(4.28\ s) + \frac{1}{2}(9.81\ m/s^2)(4.28\ s)^{2}\\[/tex]

h = 90.09 m