Across-country skier can complete a 7.5 km race in 45 min. what is the skier’s average speed?

Answer

2.7778 m/s

Explanation

Speed is rate of change of distance with time.

It is the distance covered in a unit time.  SI units of speed in m/s. Other units are Km/h, knots e.t.c

Average speed  = (total distance covered) / (total time taken)

                             = 7.5 Km / 45 Min

                             =  1/6 Km/Min

Or,

7.5Km = (7.5 × 1000) m = 7500 m

45 min = 45 × 60 2700 seconds

Average speed = 7500/2700

                           = 2.7778 m/s

answer: the rock sample is a sedimentary rock.

explanation:

it is given that:

mass of rock sample, m = 2.7 g

volume of rock sample,

so, density of rock sample will be

since, the density of rock sample is . hence, the rock sample is a sedimentary rock, whose densities varies between .