Respuesta :
Speed of ball is 19.80 m/s .
Explanation:
We have , a 2.0 kg ball is resting at the top of a 20 m hill. if the ball rolls down the entire hill,We need to find how fast will it be going.Let's find out:
We know that,
Potential energy : This is the energy possessed by an object due to it's virtue of height and is given by [tex]P.E = mgh[/tex] , where m is mass , g is acceleration due to gravity & h is height !
Kinetic energy : This is the energy possessed by an object due to it's virtue of motion and is given by [tex]K.E = \frac{1}{2}mv^2[/tex] , where m is mass & v is the velocity of object !
By conservation of energy :
⇒ [tex]P.E.=K.E[/tex]
⇒ [tex]mgh=\frac{1}{2} mv^2[/tex]
⇒ [tex]v=\sqrt{2gh}[/tex]
According to question , h=20 m i.e.
⇒ [tex]v=\sqrt{2(9.8)20}[/tex]
⇒ [tex]v=\sqrt{392}[/tex]
⇒ [tex]v=19.80m/s[/tex]
Hence , Speed of ball is 19.80 m/s .
