Answer
given,
before collision
mass of car A = m_a = 1300 kg
velocity of car A = v_a = 35 mph
mass of car B = m_b= 1000 kg
velocity of car B = v_b = 25 mph
after collision
V_a = 30 mph
V_b = 31.5 mph
Initial momentum
final momentum
here initial momentum is equal to the final momentum of the car.
hence, momentum is conserved in the collision.
1 Watt = 1 joule/second
650 watts = 650 joules/second
(650 J/sec) x (3,600 seconds/1 hour) = <em>2,340,000 Joules/hour</em>
The gap between the two flasks is partially evacuated of air creating a near vacuum which significantly reduces heat transfer by conduction or convection