RBSE Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.2

Rajasthan Board RBSE Solutions for Class 6 Maths Chapter 5 Understanding Elementary Shapes Ex 5.2 Textbook Exercise Questions and Answers.

RBSE Class 6 Maths Solutions Chapter 5 Understanding Elementary Shapes Ex 5.2

Question 1.
What fraction of a clockwise revolution does the hour hand of a clock turn through, when it goes from:
(a) 3 to 9
Answer:
In the complete clockwise revolution, the rear hand will rotate by 360°.

When the rear hand goes from 3 to 9 clockwise, it will rotate by 2 right angles, i.e. 180°.
Fraction = \(\frac{180^{\circ}}{360^{\circ}}=\frac{1}{2}\) or 2 right angles.

(b) 4 to 7
Answer:

When the rear hand goes from 4 to 7 clockwise, it will rotate by 1 right angle or 90°.
Fraction = \(\frac{90^{\circ}}{360^{\circ}}=\frac{1}{4}\) or one right angle.

(c) 7 to 10
Answer:
When the hour hand goes from 7 to 10 clockwise, it will rotate by 1 right angle or 90°.

Fraction = \(\frac{90^{\circ}}{360^{\circ}}=\frac{1}{4}\) or one right angle.

(d) 12 to 9
Answer:
When the hour hand goes from 12 to 9 clockwise, it will rotate by 3 right angles or 270°.

Fraction = \(\frac{270^{\circ}}{360^{\circ}}=\frac{3}{4}\) or three right angle.

(e) 1 to 10
Answer:
When the hour hand goes from 1 to 10 clockwise, it will rotate by 3 right angles or 270°.

Fraction = \(\frac{270^{\circ}}{360^{\circ}}=\frac{3}{4}\) or three right angle.

(f) 6 to 3
Answer:

When the hour hand goes from 6 to 3 clockwise, it will rotate by 3 right angles or 270°.
Fraction = \(\frac{270^{\circ}}{360^{\circ}}=\frac{3}{4}\) or three right angle.

Question 2.
Where will the hand of a clock stop if it:
(a) starts at 12 and makes \(\frac{1}{2}\) of a revolution, clockwise?
Answer:
In one complete clockwise revolution, the hand of the clock will rotate by 360°.

If the hour hand of the clock starts at 12 and make \(\frac{1}{2}\) of a revolution clockwise, then it will rotate by 180° and hence it will stop at 6.

(b) starts at 2 and makes \(\frac{1}{2}\) of a revolution, clockwise?
Answer:

If the hour hand of the clock starts at 2 and make \(\frac{1}{2}\) of a revolution clockwise, then it will rotate by 180° and hence it will stop at 8.

(c) starts at 5 and makes \(\frac{1}{4}\) of a revolution, clockwise?
Answer:

If the hour hand of the clock starts at 5 and make \(\frac{1}{4}\) of revolution clockwise, then it will rotate by 90° and hence it will stop at 8.

(d) starts at 5 and makes \(\frac{3}{4}\) of a revolution, clockwise?
Answer:

If the hour hand of the clock starts at 5 and make \(\frac{3}{4}\) of a revolution clockwise, then it will rotate by 270° and hence it will stop at 2.

Question 3.
Which direction will you face if you start facing:
(a) east and make \(\frac{1}{2}\) of a revolution clockwise?
(b) east and make 1\(\frac{1}{2}\) of a revolution clockwise?
(c) west and make \(\frac{3}{4}\) of a revolution anticlockwise?
(d) south and make one full revolution? (Should we specify clockwise or anti-clockwise for this last question? Why not?)
Answer:
If we revolve one complete round either in clockwise or in anticlockwise direction, then we will revolve by 360° and the two adjacent directions will be at 90° (of a complete revolution) away from each other.
(a) If we start facing east and make \(\frac{1}{2}\) a revolution clockwise, then we will face the west direction.

(b) If we start facing east and make 1\(\frac{1}{2}\) of a revolution clockwise, then we will face the west direction.

(c) If we start facing west and make \(\frac{3}{4}\) of a revolution anticlockwise, then we will face the north direction.

(d) If we start facing south and make a full revolution, then we will West again face the south direction.

When we revolve one complete round, direction of revolving does not matter. In clockwise and in anticlockwise directions we will be at our starting position. 

Question 4.
What part of a revolution have you turned through if you stand facing:
(a) east and turn clockwise to face north?
Answer:

If we start facing east and turn clockwise to face north, we have to make \(\frac{3}{4}\) of a revolution.

(b) south and turn clockwise to face east?
Answer:

If we start facing south and turn clockwise to face east, we have to make \(\frac{3}{4}\) of a revolution.

(c) west and turn clockwise to face east?
Answer:

If we start facing west and turn clockwise to face east, then we have to make \(\frac{1}{2}\) of a revolution.

Question 5.
Find the number of right angles turned through by the hour hand of a clock when it goes from :
(a) 3 to 6
Answer:
The hour hand of a clock revolves by 360° or 4 right angles in 1 complete round.
The hour hand revolves by 90° or 1 right angle when it goes from 3 to 6.

(b) 2 to 8
Answer:

The hour hand revolves by 180° or 2 right angles when it goes from 2 to 8.

(c) 5 to 11
Answer:

The hour hand revolves by 180° or 2 right angles when it goes from 5 to 11.

(d) 10 to 1
Answer:

The hour hand revolves by 90° or 1 right angle when it goes from 10 to 1.

(e) 12 to 9
Answer:

The hour hand revolves by 270° or 3 right angles when it goes from 12 to 9.

(f) 12 to 6
Answer:

The hour hand revolves by 180° or 2 right angles when it goes from 12 to 6.

Question 6.
How many right angles do you make if you start facing :
(a) south and turn clockwise to west?
Answer:
When we revolve one complete round in either clockwise or anticlockwise direction, we revolve by 360°, which is equal to 4 right angles and the two adjacent directions will be at 90° or 1 right angle away from each other.
If we start facing south and turn clockwise to west, then we make 1 right angle.

(b) north and turn anticlockwise to east?
Answer:

If we start facing north and turn anticlockwise to east, then we make 3 right angles.

(c) west and turn to west?
Answer:

If we start facing west and turn to west, then we make 1 complete round = 4 right angles.

(d) south and turn to north?
Answer:

If we start facing south and turn to north, then we make 2 right angles.

Question 7.
Where will the hour hand of a clock stop if it starts :
(a) from 6 and turns through 1 right angle?
Answer:
If the hour hand of a clock starts from 6 and turns through 1 right angle, then it will stop at 9.

(b) from 8 and turns through 2 right angles?
Answer:
If the hour hand of a clock starts from 8 and turns through 2 right angles, then it will stop at 2.

(c) from 10 and turns through 3 right angles?
Answer:
If the hour hand of a clock starts from 10 and turn through 3 right angles, then it will stop at 7.

(d) from 7 and turns through 2 straight angles?
Answer:
If the hour hand of a clock starts from 7 and turns through 2 straight angles, then it will stop at 7.

Note : We should consider only clockwise direction here.