Question

С помощью механического молота массой 600 кг обрабатывается железная поковка массой 205 кг. За 35 ударов поковка нагрелась от 10 до 18 °С. Чему равна скорость молота в момент удара? Считайте, что на нагревание поковки затрачивается 70% энергии молота. Удельная теплоёмкость железа 460 ДжДкг • К).

Answer 1

Дано:                      Решение:
m₁=600 кг.              Δt=18⁰C-10⁰C=8⁰C
m₂=205 кг.              t'=Δt/N=8⁰C/35=0,228⁰C
t₀=10⁰C                    0,7*K=Q
t₁=18⁰C                     0,7*(m₁*υ²)/2=m₂*c*t'
η=70%                      0,35*m₁*υ²=m₂*c*t'
c=460 Дж/(кг*⁰С)    υ²=(m₂*c*t')/(0,35*m₁)
N=35                        υ²=(205*460*0,228)/(0,35*600)=102,3 (м/с)²
-----------------------      υ=√102,3≈10,1 м/с
υ=?
Ответ: υ=10,1 м/с

Answer 2

Calculation of the Hammer's Speed

To calculate the speed of the hammer at the moment of impact, we can use the principle of conservation of energy. The energy transferred to the forging during the impact is equal to the work done by the hammer. The work done by the hammer can be calculated using the formula:

Work = Force × Distance

In this case, the force is the weight of the hammer, and the distance is the height from which the hammer falls. The energy transferred to the forging is then used to heat it up.

Given: - Mass of the hammer (m1) = 600 kg - Mass of the forging (m2) = 205 kg - Number of blows (n) = 35 - Temperature change (ΔT) = 18°C - 10°C = 8°C - Efficiency of energy transfer (η) = 70% = 0.7 - Specific heat capacity of iron (c) = 460 J/(kg·°C)

First, let's calculate the work done by the hammer:

Work = Force × Distance

The force can be calculated using the formula:

Force = Mass × Acceleration due to gravity

The acceleration due to gravity is approximately 9.8 m/s².

Force = 600 kg × 9.8 m/s²

Now, let's calculate the distance:

Distance = Height of fall

Unfortunately, the height of fall is not provided in the question. Could you please provide the height from which the hammer falls?