A student rolled a ball across a field with lots of rocks and pebbles. It came to a stop very quickly. The student explained that the rocks and pebbles slowed the ball
down. Give examples of different surfaces that could make the ball roll a longer
distance.

With these questions , 15 pts & brainliest

Which of the choices below is one of the primary gases found in the atmosphere? a. helium b. carbon dioxide c. nitrogen d. argon

Air is to be preheated by hot exhaust gases in a cross-flow heat exchanger before it enters the furnace. air enters the heat exchanger at 95 kpa and 20°c at a rate of 0.6 m^3/s. the combustion gases (cp = 1.10 kj/kg°c) enter at 160°c at a rate of 0.95 kg/s and leave at 95°c. determine the rate of heat transfer to the air and its outlet temperature.