A stone tied to the end of a string of 1 m long is whirled

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A stone tied to the end of a string of 1 m long is whirled in a horizontal circle with a constant speed. If the stone makes 22 revolutions in 44 seconds, what is the magnitude and direction of acceleration of the stone?

1. π² m s^–2 and direction along the radius towards the centre
2. π² m s^–2 and direction along the radius away from the centre
3. π² m s^–2 and direction along the tangent to the circle
4. π²/4 m s^–2 and direction along the radius towards the centre

Correct Option: A

a_r = ω²R & a_t =	dv	= 0
	dt

a_r = (2πn)²R = 4π²n²R² = 4π²		22		²	(1)²
		44

a_net = a_r = π²ms^–2 and direction along the radius towards the centre.