Dynamics — Quiz 5

Questions in this quiz (10)

1. The car travels along a circular curve of radius 60 ft with a constant speed of 12 ft/s. The magnitude of the acceleration (ft/s²) of the car at this instant is most nearly:

   • 1.2
   • 2.0
   • 2.4
   • 3.0

2. An electric motor is rotating at 5,000 rpm when the switch is suddenly turned off. The fan decelerates at a constant rate and comes to rest after 2 minutes. The angular deceleration of the electric fan is most nearly:

   • 2,500π rad/min²
   • 3,000π rad/min²
   • 4,000π rad/min²
   • 5,000π rad/min²

3. The angular position of a wheel traveling around a curve is described by θ(t) = 12t + 3t² − 4t³ where t is in seconds. The angular acceleration (rad/s²) at the beginning is most nearly:

   • 3
   • 6
   • 9
   • 12

4. An 8-kg block begins sliding down a 20° inclined plane. Starting from rest, the block attains a velocity of 4 m/s after 4 seconds. Most nearly, how far will the block travel in another 4 seconds?

   • 16 m
   • 24 m
   • 48 m
   • 64 m

5. If a spring is elongated by 12 cm, its potential energy is 40 J. The amount of force (N) required to elongate this spring by 24 cm is most nearly:

   • 400
   • 600
   • 800
   • 1333

6. A body of 12 kg is dropped from a height of 80 m. Its kinetic energy in Joule when it is 50 m above the ground is most nearly:

   • 3,528
   • 3,924
   • 4,708
   • 5,292

7. A 6 kg mass is allowed to fall down freely from a height of 30 m by gravitational attraction. After 3 sec, its kinetic energy in Joule is most nearly:

   • 650
   • 780
   • 1,160
   • 1,590

8. A 6 kg mass is allowed to fall down freely from a height of 30 m by gravitational attraction. After 3 sec, the potential energy (J) is most nearly:

   • 441
   • 882
   • 1,176
   • 1,764

9. An object of mass 6 kg falls from a height of 6 m on a pin and the pin enters 15 cm inside the ground. The average resisting force (N) of the ground is most nearly:

   • 1,800
   • 2,354
   • 2,940
   • 3,528

10. A car of mass 1,800 kg while descending with a velocity of 18 m/s along a road inclined to 25° with the horizontal, is brought to rest within 35 m by applying brake. The opposing force (kN) applied on the car is most nearly:

    • 12.8
    • 15.2
    • 18.6
    • 21.4