+0  
 
+1
319
1
avatar+120 

8. A track star in the long jump goes into the jump at 12 m/s and launches herself at 20.0° above the horizontal. What is the magnitude of her horizontal displacement? (Assume no air resistance and that  ay = -g = -9.81 m/s2.)

a. 4.6 m

b. 9.2 m

c. 13 m   

d. 15 m 

 

Answer's B but why.

 Aug 26, 2019
 #1
avatar+111396 
+1

The range  [ the horizontal displacement ] is given by

 

[initial velocity]^2 * sin (2 * θ)  / g   =   12^2 * sin (2*20°) / 9.81 =  12^2 * sin(40°) / 9.81   ≈  9.44m 

 

 

cool cool cool

 Aug 27, 2019

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