# Solve for Constant Torque: 75g-cm2 to Spin Yo-Yo to 300 rev/min in 1s

• reminiscent
In summary, the question asks for the constant torque needed to make a yo-yo spin to 300 rev/min in one second, starting from rest. Using the equation ∑ = Iα and assuming constant angular acceleration, the torque can be found by multiplying the angular acceleration by the moment of inertia. The resulting answer is 2.36 x 10^-4 kg*m^2/s^2.
reminiscent

## Homework Statement

A yo-yo has a moment of inertia of 75.0 g-cm2 about its rotation axis. What is the constant torque required to make it spin to 300 rev/min in one second, starting from rest?

= Iα

## The Attempt at a Solution

I was thinking since the question is asking for constant torque, angular acceleration would also have to be constant. Therefore, I would just find angular acceleration (using (ω(t) - ω0)/(t2-t1)) then multiply that angular acceleration by the moment of inertia. Is that correct thinking?

Yes, your thinking is correct. Be careful with the units.

cat__lover said:
2.36 x 10^-4 kg*m^2/s^2

## 1. What is constant torque and how does it relate to spinning a yo-yo?

Constant torque is the amount of rotational force applied to an object over a certain distance. In this case, it is the force needed to spin a yo-yo. It is important because it determines the speed at which the yo-yo will spin.

## 2. How is torque measured and what unit is used?

Torque is measured in newton-meters (Nm) or in this case, gram-centimeters (g-cm). It is calculated by multiplying the force applied (in newtons or grams) by the distance from the pivot point (in meters or centimeters).

## 3. What is the significance of the given values, 75g-cm2 and 300 rev/min?

The value of 75g-cm2 represents the constant torque needed to spin the yo-yo to achieve a speed of 300 revolutions per minute (rev/min) in 1 second. This means that the yo-yo will make 300 complete rotations in 1 minute.

## 4. How does the weight of the yo-yo affect the constant torque needed to spin it?

The weight of the yo-yo does not directly affect the constant torque needed to spin it. However, a heavier yo-yo may require a slightly higher torque due to increased inertia and friction.

## 5. What factors can affect the ability to achieve a constant torque of 75g-cm2?

The factors that can affect the ability to achieve a constant torque of 75g-cm2 include the quality of the yo-yo's bearings, the smoothness of the string, and any external forces such as air resistance or friction from the surface it is spinning on.

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