Calculate the average speed of a complete round trip in which the outgoing 300 km is covered at 93 km/h , followed by a 1.0-h lunch break, and the return 300 km is covered at 56 km/h . express your answer to two significant figures and include the appropriate units.

Answer : 63 km/h

Explanation :

Outgoing distance = 300 km.

Outgoing speed = 93 km/h.

Break time = 1 h

Return distance = 300 km

Return speed = 56 km/h

Outgoing time  = outgoing distance / outgoing speed

Outgoing time   = 300 km / 93 km/h = 3.225806451612 h

Return time  = return distance / return speed

Return time = 300 km / 56 km/h = 5.357142867142 h

Total distance =. Outgoing distance + return distance travelled

Total distance  = 300 km + 300 km = 600 km

Total time = outgoing time + break time + return time

Total time = 3.225806451612 h + 1 h+ 5. 357142867142 h = 9.582949308754 h

Average speed = total distance / total time

Average speed = 600 km / 9.582949308754 h

Average speed = 62.61120462042 km/h = 63 km/h

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.

a.   mass number from atomic number