LQ3 Physics

Which is true about uniform circular motion?

• 1. The direction of the velocity of a uniform circular motion is constant.

• The speed, or the magnitude of the velocity vector, of a uniform circular motion is constant.

• 1. The velocity of a uniform circular motion is constant, therefore, its acceleration is zero.

• All of the above statements are true.

Which of the following is not an example of centripetal force?

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Period is defined as the time required to make one complete revolution. What is the period of revolution of a man situated at the earth’s equator?

• 1. 3 600 s

• 36 000 s

• 1. 8 640 s

• 86 400 s

A circular platform with a diameter of 4 meters is spinning at a constant speed. Which point in the platform has the highest speed?

• 1. at the center

• 1 meter from the center

• 1. 2 meters from the center

• all points have the same speed

The wheels of a car have a radius of r = 0.40 m and are being rotated at ​ (a)   cycles per second. The period of revolution of each wheel is 0.067 s.

• 15
• 12
• 13
• 14

A jet flying at 123 m/s banks to make a horizontal circular turn. The radius of the turn is 3810 m, and the mass of the jet is 2.00 × 10^5 kg. Calculate the magnitude of the necessary lifting force.

_ _ _ kN

Work is a scalar quantity. Which among the following is not a unit for work?

• 1. Joule

• Newton

• 1. Newton-meter

• Dyne-centimeter

What has to happen when a force is exerted on an object for work to be done?

• 1. the object moves

• the object stays still

• 1. the force increases

• none of the above

Thor, a demigod, is the only one who can lift his hammer, Mjölnir. You, a flimsy mortal, can only try to lift. Which of the following is not true?

• 1. Work is done when Thor is lifting the hammer

• You exerting force trying to lift the hammer is considered work.

• 1. Thor lifting the hammer and putting it right back to its original position means there is no work done.

• All of the above statements are true