The answer are. Show your work 18a) 41s18b) 1734 m up18c) 200m/s down19) 20m/s South, 20m/s20a) 4m/s20b) 2.8 m/s21a) 24m Yes21b) 4.0m/s

8. A rocket is fired vertically upward with an initial velocity of 80 m/s. It accelerates upward at 4.0 m/s until it reaches an altitude of 1000 m. At that point, its engines fail and the rocket goes into free flight. How long is the rocket in motion? (3) What is the maximum altitude? (3) What is the velocity before it collides with the earth? (3) . A car is driven for 1.00 h with a velocity of 100 km/h towards the south, then for 0.50 h with a velocity of 50 km/h towards the north, and finally for 0.75 h with a velocity of 80 km/h towards the south. Find the car's average velocity and. its average speed. Express your answers in m/s. (5) 0. An object is pushed along a rough horizontal surface and released. It slides for 10.0 s before coming to rest and travels a distance of 20.0 cm during the last 1.0 s of its slide. Assuming the acceleration to be uniform throughout How fast was the object travelling upon release? b) How fast was the object travelling when it reached the halfway position in its slide? (5) A pedestrian is running at his maximum speed of 6.0 m/s trying to catch a bus that is stopped at a traffic light. When he is 16 m from the bus, the light changes and the bus pulls away from the pedestrian with an acceleration of 1.0 m/s?. a) Does the pedestrian catch the bus, and, if so, how far does he have to run? (If not, what is the pedestrian's distance of closest approach?) b) How fast is the bus moving when the pedestrian catches it? (or at the distance of closest approach). c) On a single set of axes, sketch the corresponding position-time graphs of both the bus and the pedestrian confirm your answers in (a). (8)