Agas company in massachusetts charges $1.30 for 15.0 ft^3 of natural gas. (a) convert this rate to dollars per liter of gas. (b) if it takes 0.304 ft^3 of gas to boil a liter of water, starting at room temperature (25â°c), how much would it cost to boil a 2.1l kettle of water?

Explanation:

a ) 15( ft)³ = 15 ( 12 inch )³  = 15 x 12 x 12 x 12 (inch)³ = 25920 (inch)³

=25920( 2.54 cm)³ = 25920 x 2.54 x 2.54 x 2.54 cm³ =424752.7 cc

424752.7/1000 litre = 424.75 liter

424.75 liters cost 1.30 dollars

1 liter costs    1.3/424.75 = 3.06 x 10⁻³ dollars.

So rate

= 3.06 x 10⁻³ dollars/liter

b ) one liter of water takes 0.304 ft³ of gas

2.1 liter will take 0.304 x 2.1 = 0.6384 ft³ of gas

cost = 1.3 x .6384 / 15 = 0.055328 dollar = 55.33 x 10⁻³ dollar.

(newtons first law)

conservation of momentum law states :

momentum before collision = momentum after collision

momentum p (kg-m/s)= mass * velocity

say moving car=1 000 kg, velocity = 10 m/s then p = 1 000*10= 10 000 kg-m/s

say still car = 2 000 kg, velocity = 0 m/s then p = 2 000* 0 = 0 kg-m/s

total momentum prior to collision = 10 000 + 0 = 10 000 kg-m/s

momentum after collision = 10 000 kg-m/s

mass now = 1 000 kg+2 000 kg = 3 000 kg

10 000 = 3 000 kg* velocity m/s

10 000/3 000 = velocity

3.33 m/s = velocity after collision

an impulse is a force applied over time , momentum is exclusive of external forces and a perfect collision is implied