Question 190: 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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