Question 266: Work, Energy and Power & Circular Motion

Question

A ball of mass 100 g is dropped from a height h = 10 cm on a platform fixed at the top of a vertical spring (as shown in figure). The ball stays on the platform and the platform is depressed by a distance $${h \over 2}$$. The spring constant is _____________ Nm$$-$$1.
(Use g = 10 ms$$-$$2)

Accepted Answer

$$mg\left( {h + {h \over 2}} ight) = {1 \over 2}k{\left( {{h \over 2}} ight)^2}$$
$$ \Rightarrow 0.1 	imes 10	imes(0.15) = {1 \over 2}k{(0.05)^2}$$
$$ \Rightarrow k = 120$$ N/m

Work, Energy and Power & Circular Motion

A ball of mass 100 g is dropped from a height h = 10 cm on a platform fixed at the top of a vertical spring (as shown in figure). The ball stays on the platform and the platform is depressed by a distance ${h \over 2}. The spring constant is _____________ Nm-1. (Use g = 10 ms-$2)

Choose the correct answer: