10th Science Book Back Answers Unit 1 – Law of Motions:

Samacheer Kalvi 10th Standard Science Book Back Questions with Answers PDF uploaded and the same given below. Class-tenth candidates and those preparing for TNPSC exams can check the New Science Book Back Question and Answers PDF below.  Samacheer Kalvi Class 10th Std Science Book Back Answers Physics Unit 1 – Laws of Motions Solutions are available below. Complete solutions for all 23 Units’ book back questions with a solutions guide uploaded and available on our site. Check the complete Samacheer Kalvi 10th Science Unit 1 Answers below:

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Samacheer Kalvi 10th Science Book Back Answers Physics Unit 1 – Laws of Motions

Samacheer Kalvi 10th Science Book Subject One Mark, Two Mark Guide questions and answers are below. Check Science Book Back Questions with Answers. Take the printout and use it for exam purposes.

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10th Science – Physics

Unit 1: Law of Motions

I. Choose the best answer:

1. Inertia of a body depends on
a. weight of the object     b. acceleration due to gravity of the planet
c. mass of the object        d. Both a & b
Ans: (c) mass of the object

2. Impulse is equal to
a. rate of change of momentum b. rate of force and time
c. change of momentum d. rate of change of mass
Ans: (c) change of momentum

3. Newton’s III law is applicable
a. for a body is at rest      b. for a body in motion
c. both a and b                  d. only for bodies with equal masses
Ans: (c) both (a) & (b)

4. Plotting a graph for momentum on the X-axis and time on Y-axis. the slope of momentum- time graph gives
a. Impulsive force     b. Acceleration
c. 1/Force                   d. Rate of force
Ans: (c) 1/F)

5. In which of the following sport the turning of effect of force used
a. swimming b. tennis c. cycling d. hockey

Ans: (c) cycling

6. The unit of ‘g’ is m s-2. It can be also expressed as
a. cm s–1 b. N kg–1 c. N m2 kg–1 d. cm2 s–2

Ans: (b) N Kg–1

7. One-kilogram force equals to
a. 9.8 dyne   b. 9.8 × 104 N    c. 98 × 104 dyne    d. 980 dyne
Ans: (c) 98 × 104 dyne

8. The mass of a body is measured on planet Earth as M kg. When it is taken to a planet of radius half that of the Earth then its value will be kg
a. 4 M    b. 2M    c. M/4     d. M
Ans: (c) M/4

9. If the Earth shrinks to 50% of its real radius its mass remaining the same, the weight of a body on the Earth will
a. decrease by 50%    b. increase by 50%     c. decreases by 25%     d. increase by 300%
Ans: (c) decrease by 25%

10. To project the rockets which of the following principle(s) is /are required?
a. Newton’s third law of motion          b. Newton’s law of gravitation
c. law of conservation of linear momentum  d. both a and c
Ans: (d) both (a) and (c)

II. Fill in the blanks:
1. To produce a displacement is required. Ans: Force
2. Passengers lean forward when a sudden brake is applied in a moving vehicle. This can be explained by ______. Ans: Inertia of motion
3. By convention, the clockwise moments are taken as _______, and the anticlockwise moments are taken as ______. Ans: Negative, Positive
4. _______is used to change the speed of the car. Ans: Gears
5. A man of mass 100 kg has a weight at the surface of the Earth. Ans: 980 N

III. True or False (Correct the Statement if it is false):

1. The linear momentum of a system of particles is always conserved.
Ans: False. The linear momentum of a system of particles is always conserved only if no external force is applied.

2. Apparent weight of a person is always equal to his actual weight.
Ans: False. Apparent weight and actual weight is not equal during upward or downward motion.

3. Weight of a body is greater at the equator and less at the polar region.
Ans: False. Weight of a body is lesser at the equator and more at the polar region
as g α 1 R2.

4. Turning a nut with a spanner having a short handle is so easy than one with a long handle.
Ans: False. Moment of force in longer handle is easy than one with a short handle.

5. There is no gravity in the orbiting space station around the Earth. So the astronauts feel weightlessness.
Ans: False. The apparent weight is zero. They are in a state of weightlessness.

IV. Match the following:

Answer:
1. (b) Stable equilibrium of a body
2. (c) Law of force
3. (d) Flying nature of a bird
4. (a) Propulsion of a rocket

V. Assertion and Reason:
Mark the correct choice as
a) If both the assertion and the reason are true and the reason is the correct explanation of the assertion.
b) If both the assertion and the reason are true, but the reason is not the correct explanation of the assertion.
c) Assertion is true, but the reason is false.
d) Assertion is false, but the reason is true.
Assertion: The sum of the clockwise moments is equal to the sum of the anticlockwise moment.
Reason: The principle of conservation of momentum is valid if the external force on the system is zero.
Ans: (b) both the assertion and the reason are true, but the reason is not the correct explanation of the assertion

Assertion: The value of ‘g’ decreases as height and depth increases from the surface of the Earth.
Reason:  ‘g’ depends on the mass of the object and the Earth.
Ans: (c) Assertion is true, but the reason is false.

Other Important links for 10th Science Book Answers Solutions:

For the 10th Standard Science Unit 2 book back question and answers solutions PDF, check the link – Samacheer kalvi 10th Science Unit 2 – Optics

Click here for the complete Samacheer Kalvi 10th Science Book Back Solution Guide PDF – 10th Science Book Back Solutions