Subtract the following numbers, using scientific notation and the correct number of significant digits. 6.94 × 103 mm - 4.5 × 102 mm = .

2.4 × 103 mm
2.44 × 102mm
6.49 × 103 mm
6.5 × 103 mm

The correct answer is - 6.49 × 10^3 mm.

Explanation:

The correct scientific notation of the given subtraction problem is:

6.94 × 10^3 mm - 4.5 × 10^2 mm = .

The correct number of significant digits is

a. 6.94 × 10^3 mm = 3

b. 4.5 × 10^2 mm = 2

So subtracting the 6.94 × 10^3 mm - 4.5 × 10^2 mm

= 6940 - 450

= 6.49× 10^3 mm.

a.metals can become magnetic if they have many spinning electrons that create magnetic fields.d.only some metals are attracted by magnets; these metals are called ferromagnetic.

d.wrapping an insulated wire around a metal with ferromagnetic properties and applying an electric current.

the total distance traveled by the car is

30km + 49km = 79 km .