Answer: 6.36
Explanation:
Given
Radius of grindstone, r = 4 m
Initial angular speed of grindstone, w(i) = 8 rad/s
Final angular speed of the grindstone, w(f) = 12 rad/s
Time used, t = 4 s
Angular acceleration of the grinder,
α = Δw / t
α = w(f) - w(i) / t
α = (12 - 8) / 4
α = 4/4 = 1 rad/s²
Number of complete revolution in 4s =
Δθ = w(i).t + 1/2.α.t²
Δθ = 8 * 4 + 1/2 * 1 * 4²
Δθ = 32 + 1/2 * 16
Δθ = 32 + 8
Δθ = 40 rad/s
40 rad/s = 40/2π rpm = 6.36 rpm
Therefore, the grindstone does 6.36 revolutions during the 4 s interval
Vehicle Kinematics: a
vehicle sliding sideways into a gravel pit, a vehicle
driving down a bank, a vehicle driving up a ramp and
a vehicle sliding laterally against a curb. "sliding
laterally against a curb" and "sliding sideways into a
gravel pit".
Answer:
The speed is the same as long as the reflection is regular.
Explanation:
This is because in regular reflection, the angle of incidence is equal to the angle of reflection in accordance with the second law of reflection.
Since speed of light depends on the angle of the light ray it makes with the reflecting surface, the speed is the same
