Aracehorse is running with a uniform speed of 69 km/hr along a straightaway. what is the time it takes for the horse to cover 400 meters?
21 seconds
2.1 minutes
0.35 hours
27.6 hours

21 seconds

Explanation:

First, convert km/hr to m/s.

69 km/hr × (1000 m / km) × (1 hr / 3600 s) = 19.2 m/s

Distance = rate × time

400 m = 19.2 m/s × t

t = 20.9 s

Rounded to two significant figures, it takes the horse 21 seconds.

The answer to your question is: 21 seconds

Explanation:

Data

speed = v = 69 km/h

distance = d = 400 m

time = t = ?

Formula

v = d / t

t = d / v

Process

Convert 400 m to km

                                 1 km 1000 m

                                 x       400 m

                                x = (400 x 1) / 1000

                                x = 0.4 km

Substitution

                      t = 0.4 / 69

                      t = 0.006 h

Covert time to minutes and seconds

                     60 min 1  h

                     x              0.006 h

                     x = (0.006 x 60) / 1

                     x = 0.36 min

Convert time to seconds

                     1 min  60 s

                   0.36 min   x

                     x = (0.36 x 60) / 1

                     x = 21.6 seconds  ≈ 21 seconds

0.19 m/s and 0.45 m/s

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide