Question

A 30g bullet at v=900m/s strikes a 1kg soft iron target stopping inside the iron [c=490J/kg°C. How much will the temperature of the iron increase? Ignore the heat that will be shared with the bullet

A) 25°C
B) 24795°C
C) 826°C
D) 82653°C
show your full work please

Answer 1

Answer:

ΔT = 25°C

Explanation:

Given that.

The mass of a bullet, m₁ = 30 g = 0.03 kg

The speed of the bullet, v = 900 m/s

Mass of soft iron, m₂ = 1 k

The specific heat of iron, c=490J/kg°C

We need to find the increase in temperature of iron. using the conservation of energy,

Kinetic energy = heat absorbed

$\dfrac{1}{2}m_1v^2=m_2c\Delta T\\\\\Delta T=\dfrac{\dfrac{1}{2}m_1v^2}{m_2c}\\\\\Delta T=\dfrac{\dfrac{1}{2}\times 0.03\times 900^2}{1\times 490}\\\\=24.79^{\circ} C\\\\or\\\\\Delta T=25^{\circ} C$

So, the correct option is (A).