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

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

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

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

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

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

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

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

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

#29 Calculate the instantaneous speed at the 10-second mark for a car that accelerates at 2 m/s2 from a position of rest. 20m/s

#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

#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

#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

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