+0  
 
+3
446
2
avatar+1832 

I don't understand the Formula  of this question 

 

 

xvxvxv  Sep 26, 2014

Best Answer 

 #2
avatar+94105 
+8

Let the distance travelled in the fist 5 seconds be x metres

We know u=0

When t=5, s=x

When t=10 s=x+150

I am going to use the formula     $${\mathtt{s}} = {\mathtt{ut}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{{\mathtt{at}}}^{{\mathtt{2}}}$$

since u=0,  the formula becomes  $${\mathtt{s}} = {\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{{\mathtt{at}}}^{{\mathtt{2}}}$$

Now we have 2 equations that can be solved simultaneously.

$$\\x=\frac{1}{2}a\times 5^2 \\\\\
x= \frac{1}{2}a\times 25 \qquad (1)\\\\
and\\\\
x+150=\frac{1}{2}a\times 10^2 \\\\
x+150=\frac{1}{2}a\times 100 \\\\
x+150=\frac{1}{2}a\times 25 \times 4 \\\\
\frac{x+150}{4}=\frac{1}{2}a\times 25 \qquad (2)\\\\
$putting these together I get\\\\
\begin{array}{rll}
x&=&\frac{x+150}{4}\\
4x&=&x+150\\
3x&=&150\\
x&=&50\\
\end{array}$$

 

So the ball rolls 50m in the first 5 seconds   

Melody  Sep 27, 2014
 #1
avatar+8263 
0

Is the s after the 5.0 seconds?

DragonSlayer554  Sep 26, 2014
 #2
avatar+94105 
+8
Best Answer

Let the distance travelled in the fist 5 seconds be x metres

We know u=0

When t=5, s=x

When t=10 s=x+150

I am going to use the formula     $${\mathtt{s}} = {\mathtt{ut}}{\mathtt{\,\small\textbf+\,}}{\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{{\mathtt{at}}}^{{\mathtt{2}}}$$

since u=0,  the formula becomes  $${\mathtt{s}} = {\frac{{\mathtt{1}}}{{\mathtt{2}}}}{\mathtt{\,\times\,}}{{\mathtt{at}}}^{{\mathtt{2}}}$$

Now we have 2 equations that can be solved simultaneously.

$$\\x=\frac{1}{2}a\times 5^2 \\\\\
x= \frac{1}{2}a\times 25 \qquad (1)\\\\
and\\\\
x+150=\frac{1}{2}a\times 10^2 \\\\
x+150=\frac{1}{2}a\times 100 \\\\
x+150=\frac{1}{2}a\times 25 \times 4 \\\\
\frac{x+150}{4}=\frac{1}{2}a\times 25 \qquad (2)\\\\
$putting these together I get\\\\
\begin{array}{rll}
x&=&\frac{x+150}{4}\\
4x&=&x+150\\
3x&=&150\\
x&=&50\\
\end{array}$$

 

So the ball rolls 50m in the first 5 seconds   

Melody  Sep 27, 2014

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