CBSE Class 12 Physical Education Biomechanics in Sports Assignment Set 02

Question. "Acceleration of an object is directly proportional to the force exerted upon it.
(a) Newton's Ist Law of Motion
(b) Newton's IInd Law of Motion
(c) Newton's IIIrd Law of Motion
(d) Both (a) and (b)
Answer: (b) Newton's IInd Law of Motion

Question. Newton's which law states that every object will remain at rest or in motion until any external force is applied?
(a) Newton's Ist Law of Motion
(b) Newton's IInd Law of Motion
(c) Newton's IIIrd Law of Motion
(d) Both (a) and (b)
Answer: (a) Newton's Ist Law of Motion

Question. Friction always acts ......... the motion of an object.
(a) in the same direction as
(b) perpendicular to
(c) opposite to
(d) at a 45 degree angle to
Answer: (c) opposite to

Question. Which of the following Newton's laws of motion applies to an athlete performing a high jump off a solid surface?
(a) First
(b) Second
(c) Third
(d) All of the options
Answer: (c) Third

Question. A basketball shot towards the basket follows a parabolic path due to ............. .
(a) friction with the air
(b) effect of Newton's third law of motion
(c) gravitation
(d) All of the options
Answer: (c) gravitation

Question. The force of friction ............ the motion of one body over the other.
(a) opposes
(b) supports
(c) helps
(d) does not affect
Answer: (a) opposes

Question. Static friction comes into play when ......... .
(a) two bodies are in contact and force is applied to one of them
(b) two bodies are in contact and the same force is applied to both of them
(c) two bodies are not in contact and force is applied to one of them
(d) two bodies are not in contact and the same force is applied to both of them
Answer: (a) two bodies are in contact and force is applied to one of them

Question. Dynamic friction is the force opposing motion of one body over the surface of another body when .............. .
(a) the bodies are not in contact with each other
(b) the bodies have not yet started moving
(c) one body is actually moving
(d) None of the options
Answer: (c) one body is actually moving

Question. Sliding friction is a form of dynamic friction applicable in the sport/ sporting event of
(a) running sprints
(b) broad jump
(c) tennis
(d) ice skating
Answer: (d) ice skating

Question. Rolling friction is a form of dynamic friction applicable in the sport of ............. .
(a) cricket
(b) hockey
(c) football
(d) All of the options
Answer: (d) All of the options

Question. In which of the following sports is friction beneficial for performance?
(a) Cycling
(b) Football
(c) Both (a) and (b)
(d) Neither (a) nor (b)
Answer: (b) Football

Question. ............ the bottom surface of an athlete's shoes increases friction between the shoes and the ground.
(a) Putting spikes on
(b) Polishing
(c) Streamlining
(d) None of the options
Answer: (a) Putting spikes on

Question. Friction may be reduced by ............. .
(a) roughening
(b) lubrication
(c) smoothening
(d) All of the options
Answer: (b) lubrication

Question. Badminton players rub the soles of their shoes with lime so as to ............. .
(a) reduce friction between their feet and the court
(b) increase friction between their feet and the court
(c) enable them to run faster on court
(d) None of the options
Answer: (b) increase friction between their feet and the court

Question. Rishi who was studying in class XII is a science stream student. During his Physical Education class, he got confused how Newton's Laws of Motion are useful in sports and how they can be applied in sports. But his teacher explained these laws with help of examples from sports which proved to be very helpful for him Swimming is the best example of which law of motion?
(a) Law of Inertia
(b) Law of Acceleration
(c) Law of Reaction
(d) Both (a) and (c)
Answer: (c) Law of Reaction

Question. Assertion (A) "A change in the acceleration of an object is directly proportional to the force producing it and inversely proportional to its mass."
Reason (R) Lighter mass will travel at a faster speed.
Codes
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true, but R is not the correct explanation of A
(c) A is true, but R is false
(d) A is false, but R is true
Answer: (b) Both A and R are true, but R is not the correct explanation of A

1 Mark Questions (VSA)

Question. Explain what is 'dynamic friction'.
Answer: Dynamic friction is the opposing force that comes into play when one body is actually moving over the surface of another body. Dynamic friction may be of two types, i.e. sliding friction and rolling friction.

Question. What is Newton's first law of motion?
Answer: This law states that a body at rest will remain at rest and a body in motion will remain in motion at the same speed and in the same direction till any external force is applied on it to change state.

Question. Enlist the methods of reducing friction.
Answer: Methods of reducing friction are
(i) Polishing
(ii) Lubrication
(iii) Use of ball bearings
(iv) Streamlining

Question. What is Equilibrium?
Answer: Equilibrium can be defined as a state of balance among forces acting within or upon a body.

Question. What do you understand by the term static equilibrium?
Answer: When the forces that act upon an object are equally blanced and its centre of gravity is in a static position, the object is consider to be in a state of static equilibrium.