Question

A body covers a semicircle of radius 7cm in 5seconds. find its speed

Answer 1

7 cm = 7/100 m [1 m =100 cm.]

         = 0.07 m

Circumference of the semi-circle = 2*(22/7)*0.07/2 +(2*0.07)

                                               = 44*0.01/2 + 0.14

                                              = 0.44 /2 + 0.14

                                              = 0.22 + 0.14

                                             = 0.36 m

Speed = total distance covered/time

           = 0.36 / 5

          = 0.072 m/s

(Ans): 0.072 m/s.

Answer 2

Circumference = Pi r + 2r=22/7 *0.07 +2r = 0.22+0.14

therefore distance is equal to circumference = 0.36m

speed = Distance / Time

0.36/5= 0.072m/s