A body of mass 21 kg is dragged on a horizontal rough road with a constant speed of 20km /hr .If the coefficient of friction is 0.5.Find the heat generated in one hour?

Question

Answer

Given:
Mass of the body (m) = 21 kg
Speed of the body (v) = 20 km/hr
Coefficient of friction (μ) = 0.5

To Find:
Heat generated in one hour

Formula:
The formula to calculate the heat generated due to friction is given by:
Heat (Q) = μ * m * g * d

Where:
μ = coefficient of friction
m = mass of the body
g = acceleration due to gravity (approximately 9.8 m/s²)
d = distance traveled

Calculations:
1. Convert the speed from km/hr to m/s:
Speed (v) = 20 km/hr = (20 * 1000) / (60 * 60) m/s = 5.56 m/s

2. Calculate the force of friction (F):
Force of friction (F) = μ * m * g

Given that g ≈ 9.8 m/s² and μ = 0.5:
F = 0.5 * 21 kg * 9.8 m/s² = 102.9 N

3. Calculate the distance traveled (d) in one hour:
Distance (d) = v * t
Given that time (t) = 1 hour = 60 minutes = 60 * 60 seconds = 3600 seconds:
d = 5.56 m/s * 3600 s = 20,016 m

4. Calculate the heat generated (Q) in one hour:
Heat (Q) = F * d
Q = 102.9 N * 20,016 m = 2,057,246.4 J

Answer:
The heat generated in one hour is approximately 2,057,246.4 Joules.

Answer

J=4.2.    g=10Wd=F*displacementCoefficient of friction*m*g*(v*t)W=0.5*21*10*(20*36500)    =7,560,000Heat generated Q=W/J. =7,560,000/4186=1806.02 w

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