A ball of mass 50 g falls from rest vertically downwards through a distance of 40 m and hits the ground. Find the kinetic energy and final velocity of the ball before it hits the ground (g = 9.8 ms^(-2)).

A ball of mass 50 g falls from rest vertically downwards through a dis

1.	A ball of mass 50 g falls from rest vertically downwards through a distance of 40 m and hits the ground. Find the kinetic energy and final velocity of the ball before it hits the ground (g = 9.8 ms^(-2)).
Answer» <html><body><p></p>Solution :<a href="https://interviewquestions.tuteehub.com/tag/mass-1088425" style="font-weight:bold;" target="_blank" title="Click to know more about MASS">MASS</a> of ball, m = 50 gm `= 50 <a href="https://interviewquestions.tuteehub.com/tag/xx-747671" style="font-weight:bold;" target="_blank" title="Click to know more about XX">XX</a> 10^(-3)` kg , Height of fall, h = 40 m , g = 9.8 `ms^(-2)` <br/> From law of conservation of energy, loss in P.E = gain in K.E. <br/> `<a href="https://interviewquestions.tuteehub.com/tag/rarr-1175461" style="font-weight:bold;" target="_blank" title="Click to know more about RARR">RARR</a> mgh = (1)/(2) <a href="https://interviewquestions.tuteehub.com/tag/mv-1082193" style="font-weight:bold;" target="_blank" title="Click to know more about MV">MV</a>^(2) and v = sqrt(2 gh)` <br/> K.E. = mgh `rArr` K.E. = `50 xx 10^(-3) xx 9.8 xx 40 = 19.6` J <br/> Final <a href="https://interviewquestions.tuteehub.com/tag/velocity-1444512" style="font-weight:bold;" target="_blank" title="Click to know more about VELOCITY">VELOCITY</a>, `v = sqrt(2 xx 9.8 xx 40) = 28 ms^(-1)`</body></html>