MCQs on Dynamics, Grade 9
- A 30 kg object is support from rope such that tension in the rope is equal to its weight. The weight of the object is
A. 30 kg | B. 30 N | C. 294 N | D. 9.8 N/kg |
- Force needed to produce an acceleration of 10 ms-2 in a ball of mass 0.5 kg is
A. 20 N | B. 10.5 N | C. 9.5 N | D. 5 N |
- Ball A collides with ball B which is at rest. After the collision which of the following condition is not possible
A. Ball A comes to rest and ball B starts moving | B. Both balls move in same direction | C. both balls move in opposite directions | D. both balls are at rest |
- What is the mass of a car that is travelling with a velocity of 20 m/s [W] and a momentum of 22000 kg m/s [W]
A. 440000 kg | B. 21980 kg | C. 22020 kg | D. 1100 kg |
- An object at earth and taken to should have
A. less mass/less weight | B. same/more weight | C. same mass/less weight | D. less mass/same weight |
- The unit of coefficient of friction is
A. N | B. kg | C. μ | D. It has no units |
- The centripetal acceleration of an object of mass 1 kg moving with 6 m/s in a circle of radius 3 m is
A. 18 ms-2 | B. 12 ms-2 | C. 10 ms-2 | D. 2 ms-2 |
- How many times the centripetal force will increase if the mass of a body moving with uniform speed in a circle is doubled.
10.
A. Six times | B. Two times | C. Four times | D. Eight times |
- Which of the following forces can act as centripetal forces
A. tension | B. friction | C. gravitational force | D. All of these |
- An empty suitcase is placed in the middle of a bus on its floor traveling at high speed. When the bus brakes suddenly, the suitcase slides
A. backwards | B. forward | C. jumps up | D. remains in place |
- In Newton’s third law the action reaction pair does not neutralize each other, because they
A. act on same body | B. act on different bodies | C. act on third body | D. produce friction |