Answer:
a)15 N
b)12.6 N
Explanation:
Given that
Weight of block (wt)= 21 N
μs = 0.80 and μk = 0.60
We know that
Maximum value of static friction given as
Frs = μs m g = μs .wt
by putting the values
Frs= 0.8 x 21 = 16.8 N
Value of kinetic friction
Frk= μk m g = μk .wt
By putting the values
Frk= 0.6 x 21 = 12.6 N
a)
When T = 15 N
Static friction Frs= 16.8 N
Here the value of static friction is more than tension T .It means that block will not move and the value of friction force will be equal to the tension force.
Friction force = 15 N
b)
When T= 35 N
Here value of tension force is more than maximum value of static friction that is why block will move .We know that when body is in motion then kinetic friction will act on the body.so the value of friction force in this case will be 12.6 N
Friction force = 12.6 N
1. Humidity cannot be used to predict rain.
2. I'm pretty sure it's weather but I'm not 100% sure. Maybe like 89% sure.
3. Tempurature doesn't affect humidity.
4. Not sure but I think its the 3rd one
72 m/s
Explanation:
Given,
Frequency ( f ) = 6 Hz
Wavelength ( λ ) = 12 m
To find : -
Speed ( v ) = ?
Formula : -
v = f x λ
v
= 6 x 12
= 72 m/s
Therefore,
the speed of a wave with a frequency of 6 Hz and a wavelength of 12 m is 72 m/s.
Answer:
The net gravitational force on the mass is 
Explanation:
We have by Newton's law of gravity the force of attraction between masses 

Applying vales we get
Force of attraction between 135 kg mass and 38 kg mass is

Force of attraction between 435 kg mass and 38 kg mass is

Thus the net force on mass 38.0 kg is 
Answer:
When a an object is been rotated its resistance capacity to that rotational force is know as rotational inertia and this mathematically given as

Where m is the mass
r is the rotation radius
For the spinning of the lamp as a baton to work the location of the center of mass of the floor lamp needs to be located
This is more likely to be located closer to base of the lamp as compared to the top, so success of spinning a floor lamp like a baton is highly likely if the lamp is grabbed closer to the base because that is where the position of its center of mass is likely to be.
Explanation: