When you talk about rate, you will expect that it will be in terms of a time unit. It measures how fast it is going. So, you would expect that the denominator is in time units. For the movement, you can measure this with either distance or velocity.
So, for the first variety, you would need distance and time to measure the rate of how far you go at a certain time. It is also called as velocity. For the second variety, you would need velocity and time to measure the rate of how fast you are going at a certain interval. It is also called as acceleration.
Answer:
884 balloons
Explanation:
Assume ideal gas, since temperature is constant, then the product of pressure and volume is constant.
So if pressures reduces from 100 to 1.2, the new volume would be
![V_2 = \frac{P_1V_1}{P_2} = \frac{100*0.15}{1.2} = 12.5 m^2](https://tex.z-dn.net/?f=V_2%20%3D%20%5Cfrac%7BP_1V_1%7D%7BP_2%7D%20%3D%20%5Cfrac%7B100%2A0.15%7D%7B1.2%7D%20%3D%2012.5%20m%5E2)
The spherical volume of each of the balloon of 30cm diameter (15 cm or 0.15 m in radius) is
![V_b = \frac{4}{3}\pir^3 = \frac{4}{3}\pi 0.15^3 = 0.014 m^3](https://tex.z-dn.net/?f=V_b%20%3D%20%5Cfrac%7B4%7D%7B3%7D%5Cpir%5E3%20%3D%20%5Cfrac%7B4%7D%7B3%7D%5Cpi%200.15%5E3%20%3D%200.014%20m%5E3)
The number of balloons that 12.5 m3 can fill in is
![V_2/V_b = 12.5 / 0.014 = 884](https://tex.z-dn.net/?f=V_2%2FV_b%20%3D%2012.5%20%2F%200.014%20%3D%20884)
As momentum / time = force
so; time = 100÷15
so your answer is 6.7 !!