Question

a. If an electric car is capable of going 230 km on a single charge, how many charges will it need to travel from Boston, Massachusetts, to Miami, Florida, a distance of 1486 mi?

Express your answer as an integer.

b. If a migrating loon flies at an average speed of 20 m/s , what is its average speed in mi/hr?

Express your answer using two significant figures.

c. What is the engine piston displacement in liters of an engine whose displacement is listed as 500 in3 ?

Express your answer using three significant figures.

d. In March 1989 the Exxon Valdez ran aground and spilled 240,000 barrels of crude petroleum off the coast of Alaska. One barrel of petroleum is equal to 42 gal. How many liters of petroleum were spilled?

Express your answer using two significant figures.

Answer 1

a) 1 mile = 1.609km

Distance that can be covered on a single charge = 230km

Distance that can be covered on a single charge in miles = 230km (1mi / 1.609km) = 142.95 mi

Distance between Boston and Miami = 1486 mi

Number of charge required = Distance between Boston and Miami / Distance that can be covered on a single charge

= 1486mi / 142.95mi = 10.39

So, you'll require 11 charges to cover the distance between Boston and Miami.

b) 1 mile = 1609.34 m

1 hr = 3600 s

Average speed = 20 m/s

Average speed in mi/hr = 20m/s (3600s / 1hr) (1mi / 1609.34m)

= 44.74 mi/hr

The required answer should be in two significant figures and so we rounded the solution to 45mi/hr

c) 1 inch = 2.54 cm

1 L = 1000mL = 1000cm³

Engine piston displacement = 500 in³

Engine piston displacement in litres = 500in³ (2.54cm / 1in)³ (1L / 1000cm³)

= 8.19 L

d) 1 barrel = 42 gal

1 gal = 3.785 L

Amount of petroleum spilled = 240000 barrels

Amount of petroleum spilled in litres = 240000barrel (42gal / 1barrel) (3.785L / 1gal)

= 38.15 10⁶ L

In two significant figures, the answer is 3810⁶L.