A disk of radius 10 cm speeds up from rest. it turns 60 radians reaching an angular velocity of 15 rad/s. what was the angular a
1 answer:
Answer:
a) α = 1.875
b) t = 8 s
Explanation:
Given:
ω1 = 0
ω2 = 15
theta (angular displacement) = 60 rad
*side note: you can replace regular, linear variables in kinematic equations with angular variables (must entirely replace equations with angular variables)*
a) α = ?
(ω2)^2 = (ω1)^2 + 2α(theta)
=
+ 2(α)(60)
225 = 120α
α = 1.875
b)
α = (ω2-ω1)/t
t = (ω2-ω1)/α = (15-0)/1.875 = 8
t = 8 s
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Answer:
(a) 1500 m
(b) 2827.43m
Explanation:
Given that the time for one cycle of the swing is 1 s
The radius of the swing, R= 3.0m
The angle covered, \theta, by each swing is a quarter of the circle. i.e.
Speed of running of women =5 m/s.
Time of running = 5 minutes= 5 x 60 secondes= 300 s.
(a) As distance= (speed) x (time)
So, the required distance= 5 x 300 m= 1500 m.
(b) As there are two swings in one cycle, so, the distance covered in one swing is the length of the circular shown in the figure.
As arc length, , where \theta is the angle, in radian, subtended by the arc at the center, and R is the radius of curvature of the arc.
So, the distance covered by the child in 1 swing .
In 1 cycle, there are 2 swings, so distance covered in 1 cycle .
Now, in 1 second there is 1 cycle, so in 5 minutes there will be 300 cycles.
So, the total distance covered by the child
.
