Question

4. The Spirit of Australia is a special boat called a hydroplane. It set new records by moving 384 km in only 45 minutes. What was the record-setting speed?

Answer 1

Data

distance = 384 km

time = 45 min

a) speed in km/h 60 min ---------------- 1 h

45 min ---------------- x

speed = 384 / 0.75 x = (45 x 1) / 60

speed = 512 km/h x = 45/60

x = 0.75 h

b) speed in m/s convert min to seconds

1 min ------------------ 60 seconds

45 min ------------------ x

x = (45 x 60) / 1

x = 2700 seconds

speed = 384000 / 2700

speed = 142.2 m/s

Both results are correct, but they are in different units.