a stone is dropped off a cliff. its speed after it has fallen s m is given by √19.6 s m/s. find the speed of the stone, correct to 2 decimal places after it has fallen
a) 1m b) 5m​

Answer :

Answer:

To find the speed of the stone after it has fallen a certain distance, we can use the equation for the speed of an object in free fall:

\[ \text{Speed} = \sqrt{2gh} \]

where:

- \( g = 9.8 m/s^2 \) (acceleration due to gravity)

- \( h \) is the distance fallen

Given that \( h = 1m \):

\[ \text{Speed} = \sqrt{2 * 9.8 * 1} = \sqrt{19.6} \approx 4.43 m/s \]

Rounded to two decimal places, the speed of the stone after falling 1m is approximately 4.43 m/s.

Given that \( h = 5m \):

\[ \text{Speed} = \sqrt{2 * 9.8 * 5} = \sqrt{98} \approx 9.90 m/s \]

Rounded to two decimal places, the speed of the stone after falling 5m is approximately 9.90 m/s.

Step-by-step explanation:

To find the speed of the stone when it has fallen a certain distance, we can use the equation for the speed of an object in free fall, which is \( v = \sqrt{2gh} \), where:

- \( v \) is the final speed of the stone (which is given as \( \sqrt{19.6s} \)),

- \( g \) is the acceleration due to gravity (approximately \( 9.8 \, \text{m/s}^2 \)), and

- \( h \) is the height fallen.

Given that \( v = \sqrt{19.6s} \), we can substitute this into the equation to solve for \( s \):

\[ \sqrt{19.6s} = \sqrt{2 \cdot 9.8 \cdot h} \]

Squaring both sides to eliminate the square root gives:

\[ 19.6s = 2 \cdot 9.8 \cdot h \]

\[ 19.6s = 19.6h \]

Now, solve for \( s \) using the given heights \( s = 1 \, \text{m} \) and \( s = 5 \, \text{m} \):

a) For \( s = 1 \, \text{m} \):

\[ 19.6 \cdot 1 = 19.6h \]

\[ h = 1 \, \text{m} \]

b) For \( s = 5 \, \text{m} \):

\[ 19.6 \cdot 5 = 19.6h \]

\[ h = 5 \, \text{m} \]

So, the speed of the stone, correct to 2 decimal places, after it has fallen a distance of \( 1 \, \text{m} \) is \( 1 \, \text{m/s} \) and after it has fallen a distance of \( 5 \, \text{m} \) is \( 5 \, \text{m/s} \).