1. Review Questions: Ch 2
A car starts from rest after 9 seconds is it moving at 81 m/s. What is the car’s acceleration?
81/9 = 9 m/s2

2. A car travels 8 meters in the first second, 8 meters in the second second, and 8 meters again during the thrid second. The acceleration is?
0 m/s2

3. If a projectile is fired straight up at 60 m/s, the total time to return to its starting point is?
12 seconds

4. Suppose a car is moving in a straight line and steadily increases its speed. It moves from 50 km/h to 55 km/hr in the first second and 55 km/hr to 60 km/hr in the second second. What’s the car’s acceleration?
5 km/h/s

5. A car accelerates at 4 m/s2
A car accelerates at 4 m/s2. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 40 m/s?
10 s

6. Suppose you take a trip that covers 320 km and it takes you 4 hours to make. What is your average speed?
80 km/h

7. p. 26 # 26
Calculate the avg. speed of a cheetah that runs 140 meters in 5 seconds?
28 m/s

8. p. 26 # 27
Calculate the average speed of Charlie who runs to the store 4 km away in 30 minutes.
8 km/h

9. #28
Calculate the acceleration of a car that can go from rest to 100 km/h in 10 s
10 km/h/s

10. #29
Calculate the instantaneous speed at the 10-second mark for a car that accelerates at m/s2 from a position of rest.
20m/s

11. #30
Calculate the speed of a skateboarder who accelerates from rest for 3 seconds down a ramp at an acceleration of 5 m/s2
15 m/s

12. #31
Calculate the instantaneous speed of an apple that falls freely from rest position and accelerates at 10 m/s2 for 1.5 seconds
15 m/s

13. #32
An object is dropped from rest and falls freely. After 6 seconds, calculate its instantaneous speed, average speed, and distance fallen.
Instantaneous speed=60 m/s
Avg. speed =
0m/s + 60 m/s divided by 2 ---> 30 m/s
Distance fallen =(1/2)gt2
5 (36) = 180m

14. Calculate the instantaneous speed and distance fallen for an object that falls freely from rest for 8 seconds
Avg. speed = 80 m/s
Dist. Fallen = 5 (64)
320 m