Answer: 80J
Explanation:
According to the first principle of thermodynamics:
<em>"Energy is not created, nor destroyed, but it is conserved." </em>
Then this priciple (also called Law) relates the work and the transferred heat exchanged in a system through the internal energy 
, which is neither created nor destroyed, it is only transformed. So, in this especific case of the compressed gas:
(1)
Where:
is the variation in the internal (thermal) energy of the system (the value we want to find)
is the heat transferred out of the gas (that is why it is negative)
is the work is done on the gas (as the gas is compressed, the work done on the gas must be considered positive )
On the other hand, the work done on the gas is given by:
(2)
Where:
is the constant pressure of the gas
is the variation in volume of the gas
In this case the initial volume is 
and the final volume is 
.
This means:
(3)
Substituting (3) in (2):
(4)
(5)
Substituting (5) in (1):
(6)
Finally:
This is the change in thermal energy in the compression process.
The football and air resistance between contact
Answer: be alert for pedestrians near the bus.
Explanation: Due to road accidents many Governments around the world has adopted and put in place certain rules and regulations with regards to road safety, this is so to prevent the or reduce the chances of accidents happening.
Road safety rules are rules and guidelines put in place by Government in order to prevent road accidents and maintain a free flow of traffic. An example of such rules is 'be alert for pedestrians near the bus ' when approaching a local bus that is stopped.
The statement that is true of cooling down after physical activity is that you should cool down for about 5 to 10 minutes after being physically active.
