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Higher Secondary Physics Teacher's Association is conducting Online Test series for FIRST YEAR physics students from 25-4-2020

Laws of motion

Welcome  Glad you are here,

 Dear Student, Read question and answers

Sameena C S
GHSS
ELAMKUNNAPUZHA



Q1. Select the pair of quantities which are introduced by Newton’s first law of motion

 Answer: Force and Inertia
Q2. A cyclist taking a curve leans inwards. This is due to ………….

 Answer: Provide the necessary centripetal force



Q3. A body is moving on a circular path of 10m radius. At any instant of time , its speed is 5m/s and the speed is increasing at a rate of 2 m/s2 . The magnitude of net acceleration at any instant is

Answer: 3.2 m/s2

 Hint:
Here r = 10m , v = 5m/s , at =2 m/s2 , ar = v2/r = 5x5/10 = 2.5 m/s2
The net acceleration is

 a = (ar2+at2)1/2 = ( 2.52+ 22)1/2 = (10.25)1/2 = 3.2 m/s2


 Q4. The force of friction acts.....

 Answer: Tangential to the surface of contact
Q5. When a constant force acts on a body it moves with .....

 Answer:Uniform acceleration
Q6. Walking is related to.....

 Answer: Newton’s third law of motion

Q7. The net force acting on a car of mass ‘M’ kg moving with a constant velocity ‘v’ m/s on a rough road is ......

 Answer: Zero

 Hint : Constant velocity means zero acceleration
Q8. A force of 10 N acts on a body for 0.3 seconds. The impulse is…..

 Answer:  3 Ns

Hint: Impulse = Force x time


Q9. What is the unit of "coefficient of static friction" ?

 Answer: No unit

Q10. A lift of mass (m) moving up with acceleration (a) 
.        Then tension on the rope of the lift is....

 Answer: T = mg + ma



7 comments:

  1. Basil eldhoseApril 28, 2020 at 12:56 AM

    I dont understand the 3rd question

    ReplyDelete
    Replies
    1. Higher Secondary PTAApril 28, 2020 at 5:56 AM

      a(r) is radial and a(t) is tangential acceleration
      a = (ar2+at2)1/2 = is the magnitude resultant linear resultant acceleration, since a(r) and a(t) are acting perpendicular to each other.. more doubt?..please ask

      Delete
  2. princeApril 28, 2020 at 3:50 AM

    No hint for tangential acceleration in the question

    ReplyDelete
  3. UnknownApril 28, 2020 at 4:57 AM

    I also don't understand the 3rd question

    ReplyDelete
  4. UnknownApril 28, 2020 at 8:09 AM

    I also didn't understood the 3rd question

    ReplyDelete
  5. UnknownApril 30, 2020 at 12:04 AM

    I dont understand the 10 th question

    ReplyDelete
  6. UnknownApril 30, 2020 at 12:05 AM

    I dont understand the 10 th question

    ReplyDelete

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