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Curtis, a student in our class, makes the following statement: The puck reached a slightly higher location on the ramp than I predicted. This is because I used the wrong mass for the puck when I did all my calculations. I accidentally used the mass of the smaller puck rather than the mass of the larger puck in my video." Is this a plausible explanation? Would the using the wrong mass for the puck during the calculations mean the puck would reach a greater height? Explain your reasoning.

User VcRobe
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2 Answers

10 votes

Final answer:

Curtis's explanation involving the incorrect use of the puck's mass is not plausible because, during a perfectly elastic collision, the height the puck reaches is determined by its kinetic energy and not by mass. Other factors might cause the discrepancy.

Step-by-step explanation:

No, Curtis's explanation is not plausible based on the principles of physics. In an ideal scenario, where factors like air resistance and friction are negligible, the mass of the puck does not affect the height to which it can climb on a ramp after a collision. When dealing with energy conservation and perfectly elastic collisions, the mass is not a factor in determining the maximum height after a bounce, assuming the initial and final kinetic energies are conserved and there is no energy loss.

During a perfectly elastic collision, both kinetic energy and momentum are conserved. The speed at which the puck would move after the collision depends on both pucks' masses and velocities before the collision. However, if a puck slides up a frictionless ramp after the collision, the conversion of kinetic energy to potential energy does not depend on the mass of the puck. Instead, the height attained by the puck would depend on its initial kinetic energy. Provided that the force applied and the horizontal distance before hitting the ramp remain constant, a heavier puck would carry more kinetic energy if it's moving at the same speed as a lighter puck; hence, in a real-world setting, it might reach a higher point if friction is also considered.

So, if Curtis observed a discrepancy in the height reached, it might be due to other factors like the angle of the ramp, the roughness of the surface, or inaccuracies in the initial speed measurement but not due to an incorrect mass value used in the calculations for a perfectly elastic collision scenario.

User Shaun The Sheep
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3 votes

Answer and Explanation: No, the explanation is not plausible. The puck sliding on the ice is an example of the Principle of Conservation of Energy, which can be enunciated as "total energy of a system is constant. It can be changed or transferred but the total is always the same".

When a player hit the pluck, it starts to move, gaining kinetic energy (K). As it goes up a ramp, kinetic energy decreases and potential energy (P) increases until it reaches its maximum. When potential energy is maximum, kinetic energy is zero and vice-versa.

So, at the beginning of the movement the puck only has kinetic energy. At the end, it gains potential energy until its maximum.

The representation is as followed:


K_(i)+P_(i)=K_(f)+P_(f)


K_(i)+0=0+P_(f)


(1)/(2)mv^(2) = mgh

As we noticed, mass of the object can be cancelled from the equation, making height be:


h=(v^(2))/(2g)

So, the height the puck reaches depends on velocity and acceleration due to gravity, not mass of the puck.

User Denis Kiryanov
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