Answer: When waves travel from one medium to another the frequency never changes. As waves travel into the denser medium, they slow down and wavelength decreases. Part of the wave travels faster for longer causing the wave to turn. The wave is slower but the wavelength is shorter meaning frequency remains the same.
Explanation:
Answer:
(a) 0
(b) 10ML
(c) 
(d) 
Explanation:
(a) When hanging straight down. The child is at the lowest position. His potential energy with respect to this point would also be 0.
(b) Since the rope has length L m. When the rope is horizontal, he is at L (m) high with respect to the lowest swinging position. His potential energy with respect to this point should be
where g = 10m/s2 is the gravitational acceleration.
(c) At angle 
from the vertical. Vertically speaking, the child should be at a distance of 
to the swinging point, and a vertical distance of 
to the lowest position. His potential energy to this point would be:
(d) at angle 
from the horizontal. Suppose he is higher than the horizontal line. This would mean he's at a vertical distance of 
from the swinging point and higher than it. Therefore his vertical distance to the lowest point is 
His potential energy to his point would be:
The mass on the left has a downslope weight of
W1 = 3.5kg * 9.8m/s² * sin35º = 19.7 N
The mass on the right has a downslope weight of
W2 = 8kg * 9.8m/s² * sin35º = 45.0 N
The net is 25.3 N pulling downslope to the right.
(a) Therefore we need 25.3 N of friction force.
Ff = 25.3 N = µ(m1 + m2)gcosΘ = µ * 11.5kg * 9.8m/s² * cos35º
25.3N = µ * 92.3 N
µ = 0.274
(b) total mass is 11.5 kg, and the net force is 25.3 N, so
acceleration a = F / m = 25.3N / 11.5kg = 2.2 m/s²
tension T = 8kg * (9.8sin35 - 2.2)m/s² = 27 N
Check: T = 3.5kg * (9.8sin35 + 2.2)m/s² = 27 N √
hope this helps. :)
Answer:
Explanation:
According to newton's law , force between mass m₁ and m₂ at distance x is given by the following expression
F = G m₁m₂ / x²
differentiating F with respect to x , we have
dF / d x = ₋2G m₁m₂ / x³ .
Rate of reduction of force ∝ 1 / x³
