Question 200: Work, Energy and Power & Circular Motion

Question

A  spherical ball of mass $20$ $kg$ is stationary at the top of a hill of height $100$ $m$. It rolls down a smooth surface to the ground, then climbs up another hill of height $30$ $m$ and finally rolls down to a horizontal base at a height of $20$ $m$ above the ground. The velocity attained by the ball is

Accepted Answer

Loss in potential energy $=$ gain in kinetic energy
$m 	imes g 	imes 80 = {1 \over 2}m{v^2}$
$ \Rightarrow $ $10 	imes 80 = {1 \over 2}{v^2}$
$ \Rightarrow $${v^2} = 1600$ or $v = 40\,m/s$

Answer

$20$ $m/s$

Answer

$40$ $m/s$

Answer

$10\sqrt {30} \,\,\,m/s$

Answer

$10\,\,m/s$

Work, Energy and Power & Circular Motion

A spherical ball of mass 20 kg is stationary at the top of a hill of height 100 m. It rolls down a smooth surface to the ground, then climbs up another hill of height 30 m and finally rolls down to a horizontal base at a height of 20 m above the ground. The velocity attained by the ball is

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