Question

5. If one object has a greater speed than a second object. does the first necessarily have a greater acceleration? Explain, using examples. 6. Compare the acceleration of a motorcycle that accelerates from 80 km/h to 90 km/h with the acceleration of a bicycle that accelerates from rest to 10 km/h in the same time. 7. Can an object have a northward velocity and a southward acceleration? Explain. 8. Can the velocity of an object be negative when its acceleration is positive? What about vice versa? 9. Give an example where both the velocity and accelera- tion are negative. 10. Two cars emerge side by side from a tunnel. Car A is traveling with a speed of 60 km/h and has an accelera- tion of 40 km/h/min. Car B has a speed of 40 km/h and has an acceleration of 60km/h/min. Which car is passing the other as they come out of the tunnel? Explain your reasoning. 11. Can an object be increasing in speed as its acceleration decreases? If so, give an example. If not, explain.

Answer 1

Answer:

Explanation:

5. not necessarily so that the first object could have left with initial velocity and the second not, so even if the second has a greater acceleration its velocity is less than that of the first

6. The acceleration of the motorcycle is

     SI System Reductions

     Vo = 80 km / h (1000m / 1km) (1h / 3600s) = 22.2 m / s

     Vf = 90 km / h (1000m / 1km) (1h / 3600s) = 25 m / s

     Vf = Vo + at at = Vf-Vo

     am = (Vf-Vo) / t

     am = (25 -22.2) / t = 2.8 / t

      am= 2.8/t

For the bike we have

      Vf = 10 km / h (1000m / 1km) (1h / 3600s) = 2.78 m / s

      Vo = 0

      ab = (Vf -Vo) / t

      ab = (2.78 -0) / t

      ab = 2.8/t

Since time is the same for both of us, if we round to Significant figures the two accelerations are equal

7. If when an object is slowing or slowing down.

     For example, a car goes north and must stop at the traffic light, the acceleration of the brakes goes south

8. Yes, since an object can go to the left and the acceleration to the right, but the object will lose speed over time

9. in the launch of projectiles the acceleration is negative and the speed after half the path is also negative

10. Car B must be moving to car A, because if they leave together B has more acceleration, bone that travels the distance at the same time

11. When we have friction, the velocity of an object increases by an external force, but the friction also increases the acceleration, but since it is positive, the velocity increases until the acceleration is zero and hence the velocity remains constant.