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Snuffles the Elf is sitting on a sled at the top of an icy (frictionless) hill, 5 meters above the ground. Thanks to his diminutive stature, Snuffles and his sled have a mass of 4 kg. Hoping to impress his crush, Sprinkles, Snuffles builds a snow loop with a radius of 1 m. Hoping to cushion his landing, he places a spring with a spring constant of 120 N/m after the loop.

Find the initial potential energy of Snuffles and the sled at point A.
Find the velocity of Snuffles and the sled at point B.
Find the velocity of Snuffles and the sled at the top of the loop at point C.
How much will Snuffles and the sled compress the spring before coming to a stop?

1 Answer

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Final answer:

The initial potential energy at point A is 196 J. The velocity at point B is 7 m/s. The velocity at the top of the loop at point C is also 7 m/s. The spring will compress by approximately 0.33 m before coming to a stop.

Step-by-step explanation:

The initial potential energy of Snuffles and the sled at point A can be calculated using the formula for gravitational potential energy:

PEinitial = mgh

Where m is the mass (4 kg), g is the acceleration due to gravity (9.8 m/s²), and h is the height (5 m). Plugging in the values, we get:

PEinitial = (4 kg) * (9.8 m/s²) * (5 m) = 196 J

To find the velocity of Snuffles and the sled at point B, we can use the conservation of mechanical energy:

PEinitial + KEinitial = PEfinal + KEfinal

Since the potential energy at point B is zero (ground level), we can simplify the equation to:

KEinitial = KEfinal

Using the formula for kinetic energy:

KE = 0.5 * m * v²

Where m is the mass and v is the velocity, we can plug in the values and solve for v:

0.5 * 4 kg * vB² = 196 J

vB = √(196 J / (0.5 * 4 kg)) = 7 m/s

To find the velocity of Snuffles and the sled at the top of the loop at point C, we can use the principle of conservation of mechanical energy again:

PEinitial + KEinitial = PEfinal + KEfinal

At the top of the loop, the potential energy is:

PEfinal = mgh = (4 kg) * (9.8 m/s²) * (5 m) = 196 J

Using the same formula for kinetic energy, we can solve for vC:

KEinitial = 0.5 * m * vC²

0.5 * 4 kg * vC² = 196 J

vC = √(196 J / (0.5 * 4 kg)) = 7 m/s

To find how much Snuffles and the sled will compress the spring before coming to a stop, we can use Hooke's Law:

F = k * x

Where F is the force, k is the spring constant (120 N/m), and x is the displacement (compression of the spring). We need to find the displacement at which the force becomes zero, which is the maximum compression. Rearranging the equation, we get:

x = F / k

Plugging in the values, we get:

x = (4 kg * 9.8 m/s²) / 120 N/m ≈ 0.33 m

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