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Charlie Brown kicks a ball at 22.5 m/s at 33.0 degrees. How far has the ball moved horizontally when it reaches its highest point?

 Nov 5, 2016
 #1
avatar+33653 
0

Initial vertical velocity uh = 22.5*sin(33deg) m/s

 

At the highest point the vertical velocity is zero, so using v = u + at we have:

0 = 22.5*sin(33deg) - 9.8t. where the acceleration of gravity is 9.81m/s2 downwards.  From this you can get the time, t, in seconds.

 

The horizontal velocity is given by uh = 22.5*cos(33deg) m/s so the distance (in metres) travelled in time t is given by multiplying this velocity by the value found for t.

 Nov 6, 2016
 #2
avatar+14986 
+5

Charlie Brown kicks a ball at v0 = 22.5 m/s at α = 33.0 degrees. How far has the ball moved horizontally when it reaches its highest point?

 

I decompose v0 into the vertical and horizontal component.

 

\(v_{h} = v_0\times cos \alpha=22.5\frac{m}{s}\times cos\ 33°= 18.87\frac{m}{s}\)

 

\(v_{v}= v_0\times sin\ \alpha = 22.5\frac{m}{s}\times sin\ 33°=12.2544\ \frac{m}{s}\)

 

The vertical component vy is zero at the highest point.

 

\(v_0\times sin\ \alpha-g\times t =0\)

 

\(\LARGE t= \frac{v_0\times sin \ \alpha}{g}\) \(\LARGE= \frac{22.5\frac{m}{s}\times sin \ 33°}{9.81\frac{m}{s^2}}\)

 

\({\color{blue}\large t = 1.249 \ s}\)

 

\({\color{blue}The \ ball \ has \ reached \ the \ highest \ point}\)

\({\color{blue}of \ the \ throwing \ parcel \ after \ 1.249 s.}\)

 

 \(w= v_h \times t =18.87\ \frac{m}{s}\times 1.249\ s\)

 

\({\color{blue}\large w=23.569\ m}\)

 

\({\color{blue}The \ ball \ has \ a \ horizontal \ distance \ of \ 23.569\ m }\)

\({\color{blue}when \ it \ is \ at \ the \ highest \ point }\)

\({\color{blue}of \ the \ throwing \ parabola.}\)                 laugh  !

 

 

 

 

 

\(\)

 Nov 6, 2016

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