Answer:
the yellow one
Explanation:
2 of the same elements resolute as the same element
The girl will hear an ECHO of the sounds that reach her,
(if she is standing more than about 50 feet from the wall).
Answer:
a. the density will not change
b. D' = 0.125 D
So, the density will change by a factor of 0.125
Explanation:
a.
Density is the material property and the value of density is constant for all solid materials. So, when the dimensions of the a solid are increased, while the material is same, then the material must be added to the object for increasing its dimensions. So, with the increase in the volume, the mass of the object also increases. And as a result the density of the object remains constant.
Since, here the material remains the same.
<u>Therefore, the density will not change</u>
<u></u>
b.
Density = mass/Volume
D = m/V ------------ equation (1)
Now,
V = LWH ----------- equation (2)
Now, if each dimension increases by a factor of 2, the volume becomes:
V' = (2L)(2W)(2H)
V' = 8 LWH
using equation (2)
V' = 8 V
So, for constant mass, density becomes:
D' = m/V'
D' = m/8V
using equation (1)
D' = D/8
<u>D' = 0.125 D</u>
<u>So, the density will change by a factor of 0.125</u>
Answer:
t = 0.319 s
Explanation:
With the sudden movement of the athlete a pulse is formed that takes time to move along the rope, the speed of the rope is given by
v = √T/λ
Linear density is
λ = m / L
λ = 4/20
λ = 0.2 kg / m
The tension in the rope is equal to the athlete's weight, suppose it has a mass of m = 80 kg
T = W = mg
T = 80 9.8
T = 784 N
The pulse rate is
v = √(784 / 0.2)
v = 62.6 m / s
The time it takes to reach the hook can be searched with kinematics
v = x / t
t = x / v
t = 20 / 62.6
t = 0.319 s
