1. Problems Velocity & Acceleration Physical Science

2. 1. A car’s velocity changes from 0 m/sec to 30 m/sec 10 seconds later. Calculate the car’s average acceleration. a = velocity final – velocity initial time a= 30 m/sec - 0 m/sec 10 seconds a = 3 m/sec 2

3. 2. A roller coaster starts down a hill at 10 m/sec. Three seconds later, speed increased to 32 m/sec. What is the acceleration? a = velocity final – velocity initial time a = 32m/sec – 0 m/sec 3 sec a = 10.7 m/ 2

4. 3. A swimmer speeds up from 1.1 m/sec to 1.3 m/sec during the last 20 seconds. What was the acceleration? a = velocity final – velocity initial time a= 1.3 m/sec – 1.1 m/sec 20 sec a = 0.01 m/sec 2

5. 4. A satellite has an initial velocity of 10,000 m/sec. After a minute it is 5000 m/sec. What is the satellite’s acceleration? a = velocity final – velocity initial time a = 5000 m/sec – 10,000 m/sec 60 sec a = - 83.3 m/sec 2

6. Speed and Acc Ch 3 # 1 A car traveled 1025 km from El Paso to Dallas in 13.5 hrs. What was the average velocity? Vave = distance time Vave = 1025 km 13.5 hrs Vave = 75.9 km/hour

7. 2. A car traveling north with a velocity of 30 m/sec slows down to a velocity of 10 m/s within 10 seconds. What is the car’s acceleration? a = velocity final – velocity initial time a = 10 m/sec – 30 m/sec = -20 m/sec 10 sec 10 sec a = -2 m/sec/sec or 2 m/sec 2

8. 3. If the average speed of a car is 45 km/hr, how far can it travel in 40 min? Vave = distance distance = Vave X time time distance = 45 km/hr X 40/60 minute distance = 30 km

9. 4. Falling objects drop with an average acc of 9.8 m/sec/sec. If an object falls from a tall building, how long will it take before it reaches a speed of 49 m/sec? a = velocity final – velocity initial time time = velocity final – velocity initial a time = 49 m/sec – 0 m/sec 9.8 m/sec 2 Time = 5 seconds