Question

The tension in a pulley belt is 31 N when stationary. Calculate power in watts transmitted when the belt is on the point of slipping on the smaller wheel. the wheel is 379 mm diameter and the coefficient of friction is 0.3. The angle of lap is 1610. The wheel speed is 1,547 rev/min.

Answer 1

P = 756.84 Watts

Step-by-step explanation:

As the tension is stationary or innitial, T₀ = 31 N, the mean would be:

T₁ + T₂ / 2 = T₀ (1)

T₁ + T₂ = 2 * 31 = 62 N

Now, with the following expression we can determine the linear speed:

V = πWD (2)

W: angular speed of the wheel (rev/s)

D: diameter of the wheel (in meters)

W = 1547 rev/min * (1 min/60 s) = 25.78 rev/s

V = π * 25.78 * 0.379 = 30.695 m/s

We also know that:

T₁ / T₂ = exp (μθ)

T₁ = T₂ exp(μθ) (3)

We already have those values so replacing:

T₁ = T₂ exp(0.3 * 161 * π/180)

T₁ = 2.32T₂ (4)

We can now replace (4) in (1) like this:

T₁ + T₂ = 62 N

2.32T₂ + T₂ = 62

3.32T₂ = 62

T₂ = 18.67 N

Which means that T₁:

T₁ = 2.32(18.67)

T₁ = 43.33 N

Finally, the power can be determined using the following expression:

P = (T₁ - T₂)V (5) Replacing we have:

P = (43.33 - 18.67)*30.695

P = 756.84 Watts

Hope this helps