Speed and Acceleration Solutions

SPEED AND ACCELERATION SOLUTIONS

Acceleration = ratio of change in speed to time spent in changing speed.

Note: units for acceleration are units of speed divided by units of time. For example, mph per second, or m/s per second, or cm/s per second, or m/s per nanosecond.

1. Given v = 10 m/s, and t = 2 s, find a. a = __5___m/s per s

2. Given an object’s change in speed is 10 m/s, and time is one minute, find a, in MKS units.

a = 10 m/s per minute = .17 m/s per s

3.a. Given vi = 19 m/s and vf = 21 m/s, and t = 2 s, find a.a = 1 m/s per second

b. Given vi = 19 m/s and vf = 21 m/s, and t = 1 s, find a.a = 2 m/s per second

c. Given vi = 19 m/s and vf = 21 m/s, and t = .5 s, find a.a = 4 m/s per second

4. v = -6 m/s, and t = 3 s. Find acceleration. a = -2 m/s per second

5. Given vi = 42 m/s and vf = 32 m/s, and t = 2 s, find a. a = -5 m/s per second

6. A rocket is initially moving at 25 km/s. It accelerates to 39 km/s, over the course of 2.0 seconds. What was its acceleration?

a = __ 7__ km/s per second = _7000_m/s per second.

7. Given a = .5 m/s per second, and t = 2 seconds, find v.v=at=1 m/s

8. Given a = 5 mph per second, and t = 4.2 seconds, find v. v=at= 21 mph

9. Given a = 2 m/s per millisecond, and t = 3 milliseconds, find v.

v = at = 2 m/s per ms x 3 ms = 6 m/s

10. If a = 10 m/s per s, and v = 20 m/s, what is t?t = 2 s

11. An object gains 30 m/s of speed as it accelerates at a rate of 2 m/s per second. How much time does this take? t = 15 s

12. If a car accelerates at a = 3 mph per second, how much time does it take to gain 60 mph of speed? t = 20 s

13. What is the average speed of an object that travels 5.00 meters north in 2.00 seconds and then travels 4.00 meters east in 1.00 seconds, over the course of the entire trip? Average speed for a trip is (total distance)/(total time).

= 3.00 m/s

14. A car is traveling at 60 kilometers per hour. Determine the time required for the car to travel 12 kilometers.

t = 0.2 hours, which is 12 minutes, which is 720 seconds

15. A particle is accelerated uniformly (that means with a constant acceleration, a single value of acceleration) from rest to a speed of 50 meters per second in 5.0 seconds. (a) What is the average speed of the particle during this 5.0-second time interval? (b) What is its acceleration during this time?

a) Use

b) =10 m/s per second

16. A particle undergoes a constant acceleration of Zm/s per second. Determine the time required for the particle to accelerate from 8.0 meters per second to 28 meters per second.

Z m/s per second =

t = 20/Z sec (20 divided by yourZ number)

17. An object has zero acceleration. (a) Could this object be at rest, and still have zero acceleration? (b) Could it be slowing down, and still have zero acceleration? (c) Could it be speeding up, and still have zero acceleration? (d) Could it be moving in any way, and still have zero acceleration? Two, and only two, of these are possible. Can you give an example of each??

a) Yes. example: parked car

b) no

c) no

d) YES. example: car moving at a constant speed of 30 mph