Question

Carry out these conversions: (a) a 6.0-ft person weighs 168 lb. express this person’s height in meters and weight in kilograms. (1 lb 453.6 g; 1 m 3.28 ft.) (b) the current speed limit in some states in the united states is 55 miles per hour. what is the speed limit in kilometers per hour? (c) the speed of light is 3.0 1010 cm/s. how many miles does light travel in 1 hour? (d) lead is a toxic substance. the "normal" lead content in human blood is about 0.40 part per million (that is, 0.40 g of lead per million grams of blood). a value of 0.80 part per million (ppm) is considered to be dangerous. how many grams of lead are contained in 6.0 103 g of blood (the amount in an average adult) if the lead content is 0.62 ppm?

Answer 1

A 6.0-ft person is 1.83 meters tall, and their weight of 168 lb is equivalent to 76.2 kg. The speed limit of 55 mph converts to 88.5 km/h. In 6.0 × 10³ g of blood with a lead content of 0.62 ppm, there are 3.72 g of lead.

Step-by-step explanation:

To convert the height of a 6.0-ft person to meters, we use the conversion factor 1 m = 3.28 ft:

1. Height in meters = 6.0 ft × (1 m / 3.28 ft) = 1.83 m (rounded to two decimal places).

To express this person's weight in kilograms, we use the conversion factor 1 lb = 0.4536 kg:

1. Weight in kilograms = 168 lb × (0.4536 kg / 1 lb) = 76.2 kg (rounded to one decimal place).

The conversion from 55 miles per hour to kilometers per hour can be done using the factor 1 mile = 1.60934 kilometers:

1. Speed in kilometers per hour = 55 mph × (1.60934 km / 1 mile) = 88.5 km/h (rounded to one decimal place).

To find out how many grams of lead are in 6.0 × 10³ g of blood with a lead content of 0.62 ppm:

1. Grams of lead = (0.62 g of lead / 1,000,000 g of blood) × 6.0 × 10³ g of blood = 3.72 g of lead (rounded to two decimal places).