Answer:
2gcm⁻³
Explanation:
Given parameters:
Mass of the object = 20g
Volume = 10mL
Unknown:
Density of the object = ?
Solution:
Density of a body is its mass per unit volume;
Density =
We need to convert mL to cm³ for the volume
1mL = 1cm³;
10mL is therefore, 10cm³
So;
Density = = 2gcm⁻³
The initial temperature is 137.34 °C.
<u>Explanation:</u>
As the specific heat formula says that the heat energy required is directly proportional to the mass and change in temperature of the system.
Q = mcΔT
So, here the mass m is given as 23 kg, the specific heat of steel is given as c = 490 J/kg°C and the initial temperature is required to find with the final temperature being 140 °C. Also the heat energy required is 30,000 J.
ΔT =
ΔT =
Since the difference in temperature is 2.66, then the initial temperature will be
Final temperature - Initial temperature = Change in temperature
140-Initial temperature = 2.66
Initial temperature = 140-2.66 = 137.34 °C
Thus, the initial temperature is 137.34 °C.