Clock
Questions
Q1.
Find the angle between the minute hand of a clock and the hour hand when the time is 7.20 A.M .
Solution.
as we know that , angle traced by the hour hand in 12 hrs = 360°
So , angle traced by the hour hand in 7 hr 20 minute
=
360/12
x
22/23
= 220°
we also know that angle traced by minute hand in 60 minute = 360° So, angle traced by the minute hand in 20 minute
=
360/60
x 20 =
120°
required angle between two hands = 220° - 120° = 100°
Solution
Q2.
1 radian = _________ right angles
Solution
Q3.
Which one is true :
(a) Radian is constant angle .
(b) Angle between two consecutive digit in a clock is 30°
(c) The minute hand rotate through an angle of 6° in one minute .
Solution.
All are true
Solution
Q4.
The minute hand of a watch is 2 cm long . How far does its tip move in 40 minute .
Solution.
angle traced by the minute hand in 40 minutes is = 240° = (4π/3) radian
θ = r/radius
r = θ x
radius = (4π/3) x 2 = (8π/3)
Solution
Q5.
At what angle are the hands of a clock inclined at 25 minutes past 5 .
Solution.
At 25 minute past 5 , the min hand is at 5 and hour hand slightly ahead of 5
The hour hand move by an angle of 30° in
60 min
∴ in 25 minutes , the hour hand move by an angle of (30/60) x 25 = 12.5°
the angle between two hands = 12.5°
Solution
