một viên đạn được bắn lên với vận tốc v0=800m/s theo phương hợp với mặt phẳng nằm ngang một góc 30 độ. xác định tầm xa của viên đạn

Step 1 First Draw a Diagram.

Step 2 Identify the givens

g= -9.8 m/sec2

x0 = 0 m

Y-Yo= 80m

V0 = 800m/s -30o inclined from horizontal

Xf= ?

t = ?

Step 3  * A 2 dimensional problem so break it down into x component and y component

Step 4   x component  

x= [Vox ][cos 30o][t]

x= [800m/s][cos 30o][tsec]

x=[692.8m/s][tsec]       <Need t

Step 5 y component

Y-Yo= Voy - 1/2gt2

80m= -[v][sin30o][t] -1/2gt2

1/2gt2+[v][sin30o][t]+80m=0   <Form Quadratic Equation

Solve for t

t=   -[v sin 30]  +/-   [(v sin 30)-(4)(1/2)(9.8)(80)]1/2

                      (2)(1/2)(9.8)

t= 400+/- 398

        9.8

t= 0.2 sec

Step 6 Plug this into initial x component equation

x=[692.8m/s][tsec]

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explanation:

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