Answer:
41°
Explanation:
Kinetic energy at bottom = potential energy at top
½ mv² = mgh
½ v² = gh
h = v²/(2g)
h = (2.4 m/s)² / (2 × 9.8 m/s²)
h = 0.294 m
The pendulum rises to a height of above the bottom. To determine the angle, we need to use trigonometry (see attached diagram).
L − h = L cos θ
cos θ = (L − h) / L
cos θ = (1.2 − 0.294) / 1.2
θ = 41.0°
Rounded to two significant figures, the pendulum makes a maximum angle of 41° with the vertical.
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
.
