Question 252: Work, Energy and Power & Circular Motion

Question

A 0.4 kg mass takes 8s to reach ground when dropped from a certain height 'P' above surface of earth. The loss of potential energy in the last second of fall is __________ J.
(Take g = 10 m/s$$^2$$)

Accepted Answer

Displacement is $8^{	ext {th }}$ sec.
$\mathrm{S}_{8}=0+\frac{1}{2} 	imes 10 	imes(2 	imes 8-1)$
$\mathbf{S}_{8}=5 	imes 15$
$\Delta \mathrm{U}=0.4 	imes 10 	imes 5 	imes 15$
$\Delta \mathrm{U}=20 	imes 15=300$

Work, Energy and Power & Circular Motion

A 0.4 kg mass takes 8s to reach ground when dropped from a certain height 'P' above surface of earth. The loss of potential energy in the last second of fall is __________ J. (Take g = 10 m/s$^2$)

Choose the correct answer: