A postman needs to deliver a parcel to Peter's house 5 kilometers away from the post office. He first rides a bike for 4

kilometers, and then walks the remaining 1 km. It takes the

postman 1 hour to reach Peter's house. What is the postman's

average speed (in km/hr)?

10 points! will mark brainiest! in a heat engine if 1,000 j of heat enters the system and the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2,000 j 1: write the equation 2: list out your known variables 3: plug the numbers into the equations 4: solve 5: write your solution statement that includes initial energy and final energy added you so much!