Monday, 19 February 2018

Chapter 13: Motion and Time


Q.1 Identify the wrong one:
(a)Second is the unit of time.
(b)The speed of all objects are same.
(c)Measurement of distance between two cities is in kilometers.
(d)The pendulum time period is not constant.
(e)The train speed is expressed in m/h

Q.2.A pendulum takes 40s to complete 25 oscillations. Find the pendulum’s time period.

Q.3. Two stations are 450km apart. A train takes 6hrs to cover this distance. What is the train’s speed?
  
Q.4. Draw the distance-time graph for the following case:
(a) A car moving at a constant speed.
(b) A car parked on a side road.

Q.5.The unit of speed is:
(a) km/min (b) m/min (c) km/h (d) m/s

 Q.6.The distance-time graph for the motion of two vehicles X and Y are shown below. Which of the following moves fast?
12

Q.7. Identify the one in which the truck is not moving with a constant speed from the given distance-time graph.
13 13.2


Chapter 8: Body Movements

1) Fill in the blanks:
(a) Joints of the bones help in the _______________ of the body.
(b) A combination of bones and cartilages forms the _____________of the body.
(c) The bones at the elbow are joined by a   ______________.
(d) The contraction of the ______________ pulls the bones during.

2) Indicate ‘true’ and false’ among the following sentences:
(a)The movement and locomotion of all animals are the same.
(b)The cartilages are harder than bones.
(c)The finger bones do not have joints.
(d)The forearm has two bones.
(e)Cockroaches have an outer skeleton

3) Match the items in column I with one or more items of column II:
Column I                                                              Column II
(i)Upper jaw                                                 (a) have fins on the body
(ii)Fish                                                           (b) has an outer skeleton
(iii)Ribs                                                          (c) can fly in the air
(iv)Snail                                                          (d) is an immovable joint
(v)Cockroach                                                  (e) protect the heart
   4) Answer the following questions:
(a)What is a ball and socket joint?
(b)Which of the skull bones are movable?
(c)Why can’t our elbow not move backward?
Solution:
(a)The rounded end of the one bone fits into the hollow space of other bone. This is calleda ball and socket joint. Ball and socket joints allow movements in all the directions, e.g. shoulder and hip can be moved in all directions.
(b)In the skull, only the lower jaw is movable.
(c)Our elbow cannot move backward because the elbow has a hinge joint that allows movement in only one direction.

VERY SHORT ANSWER TYPE QUESTIONS
1) Give two examples of ball and socket joint
2) Give an example of a pivotal j
3) Give two examples of hinge joints
4) Give an example of a fixed joint.

5) Give an example of a gliding joint.
6) What is a skeleton
7) Name the three components of theskeleton.
Answer: Skeleton is made up of many bones, joints and cartilage.
8) Name the parts of the body, which help in movement.
9) Name two animals, which move without bones