To solve this problem, we should recall the law of
conservation of energy. That is, the heat lost by the aluminium must be equal
to the heat gained by the cold water. This is expressed in change in enthalpies
therefore:
- ΔH aluminium = ΔH water
where ΔH = m Cp (T2 – T1)
The negative sign simply means heat is lost. Therefore we
calculate for the mass of water (m):
- 0.5 (900) (20 – 200) = m (4186) (20 – 0)
m = 0.9675 kg
Using same mass of water and initial temperature, the final
temperature T of a 1.0 kg aluminium block is:
- 1 (900) (T – 200) = 0.9675 (4186) (T – 0)
- 900 T + 180,000 = 4050 T
4950 T = 180,000
T = 36.36°C
The final temperature of the water and block is 36.36°C
Answer:
Safety
Explanation:
Expressways are banked to resist centifugal action
Answer:
The average acceleration of the ball during the collision with the wall is 
Explanation:
<u>Known Data</u>
We will asume initial speed has a negative direction, 
, final speed has a positive direction, 
, 
and mass 
.
<u>Initial momentum</u>
<u>final momentum</u>
<u>Impulse</u>
<u>Average Force</u>
<u>Average acceleration</u>
, so 
.
Therefore, 
Answer:
Given: mass 1200kg
initial velocity: 4m/s
finial velocity: 10 m/s
time 3 sec
then
speed; initial velocity + final velocity/2
4+10/3
: 4.66m/s2
