I assume the 100 N force is a pulling force directed up the incline.
The net forces on the block acting parallel and perpendicular to the incline are
∑ F[para] = 100 N - F[friction] = 0
∑ F[perp] = F[normal] - mg cos(30°) = 0
The friction in this case is the maximum static friction - the block is held at rest by static friction, and a minimum 100 N force is required to get the block to start sliding up the incline.
Then
F[friction] = 100 N
F[normal] = mg cos(30°) = (10 kg) (9.8 m/s²) cos(30°) ≈ 84.9 N
If µ is the coefficient of static friction, then
F[friction] = µ F[normal]
⇒ µ = (100 N) / (84.9 N) ≈ 1.2
The acceleration due to gravity of Mars is 
<u>Explanation:</u>
As per universal law of gravity, the gravitational force is directly proportional to the product of masses and inversely proportional to the square of the distance between them. But in the present case, the gravity need to be determined between Mars and the object on Mars. Since the mass of Mars is greater than the mass of any object. Thus,

Here, G is the gravitational constant, R is the radius of Mars and M, m is the mass of Mars and the object respectively..
Also, according to Newton’s second law of motion, the acceleration of any object will be equal to the ratio of force exerted on it to the mass of the object.
So in order to determine the acceleration due to gravity of Mars, divide the gravitational force of Mars by mass of object on the surface of Mars.




<u>Answer:</u>
0.24 m
<u>Explanation:</u>
Given:
Wave velocity ( v ) = 360 m / sec
Frequency ( f ) = 1500 Hz
We have to calculate wavelength ( λ ):
We know:
v = λ / t [ f = 1 / t ]
v = λ f
= > λ = v / f
Putting values here we get:
= > λ = 360 / 1500 m
= > λ = 36 / 150 m
= > λ = 0.24 m
Hence, wavelength of sound is 0.24 m.
So you can use the equation force = mass x acceleration to do 2 x 5 to get 10 N