Answer:
Both are moving at 30 km/h, so their speed is the same. ... enough fuel for the trip/how long it will take. 4 Weight is a force, and so is a vector. ... c At 10 seconds David's displacement is.
Answer:
16.32 °C
Explanation:
We are given;
Mass of aluminum bowl; m_b = 0.25 kg
Mass of soup; m_s = 0.8 kg
Thus, formula to find the amount of heat energy for a temperature change of 27.6°C to 0°C is;
Q = (m_b•c_b•Δt) + (m_s•c_s•Δt)
Where;
c_b = 0.215 kcal/(kg•°C)
c_s = 1 kcal/(kg•°C)
ΔT = 27.6 - 0 = 27.6°C
Thus;
Q = (0.25 × 0.215 × 27.6) + (0.8 × 1 × 27.6)
Q = 23.5635 Kcal
Now, the energy that exits to be used to freeze the soup is;
Q' = 424 kJ - Q
Let's convert 424 KJ to Kcal
424 KJ = 424/4.184 Kcal = 101.3384 Kcal
Thus;
Q' = 101.3384 - 23.5635
Q' = 77.7749 Kcal
Amount of heat that's removed is given by;
Q_f = Q' - mL
Where;
m = m_s = 0.8 kg
L = 79.8 kcal/kg
Thus;
Q_f = 77.7749 - (0.8 × 79.8)
Q_f = 13.9349 Kcal
Then final temperature will be;
T_f = Q_f/((m_b•c_b) + (m_s•c_s))
T_f = 13.9349/((0.25 × 0.215) + (0.8 × 1))
T_f = 16.32 °C
Assuming that there is no heat loss, and the cup is perfectly insulated, all of the energy lost by the lead will be absorbed by the water.
The heat absorbed is given by:
Energy = mass * specific heat capacity * change in temperature
The specific heat capacity of water is 4.18 joules per gram.
In order to compute the mass, we will use the fact that the density of water is one gram per milliliter. Therefore, the mass of water is 50 grams.
Now,
Q = 50 * 4.18 * (20 - 18)
Q = 418 J
418 Joules of energy were released by the lead.