Question

grinding wheel attend a velocity 20 Radian per second in 5 seconds starting from days find the number of revolutions made by the wheel

Answer 1

It should be “……starting from rest……”

Angular acceleration of wheel is
α = (ωf - ωi) / t
= (20 rad/s - 0) / (5 s)
= 4 rad/s²

θ = (ωi × t) + 0.5αt²
= 0 + (0.5 × 4 rad/s² × (5 s)²)
= 50 rad

Number of revolutions = 50 rad / (2 π rad) ≈ 8

Wheel made 8 revolutions in 5 seconds

Answer 2

Answer:

25/pi

Explanation:

u = 0                                                                                            

v = 20 rad/s

t = 5 s

s =( v + u)/2  * t

  =(20+0)/2   * 5

  = 10 * 5

  =50 rad

No. of revolutions = 50rad/2pi                          ....(1 revolution = 2 pi )

                               =25/pi  revolutions / sec