Answer : The static friction depends on two factors
1. Roughness of the surface
2. Force
Explanation : Friction occur when surface is not smooth.
The formula of friction is

Static friction depends on the roughness of the surface and force which is trying to push to object along the surface.
Static friction is caused by the attraction between two surfaces that are in contact. when the surface will rough and the object will heavier then the force will be larger.
Answer:
B. +5.75 m/s
Explanation:
When there are two bodies, a and b, whose velocities measured by a third observer (in this case, the ground) are
and
respectively, the relative velocity of B with respect to A is given by:

Thus, the velocity of the girl relative to the lawnmower is:

<span>Given:
3,500 kilometers
Find:</span>
Years for two continents to collide = ?
<span>Solution:
We know that </span>typical motions of one plate relative to another
are 1 centimeter per year.
So first, we convert 3,500 km to cm.<span>
</span><span>
</span>
The solution would be like this for this specific problem:
1 km = 100,000 cm
3,500 km x 100,000 = 350,000,000 cm
Since we know that 1 cm = 1 year, then that means
350,000,000 cm is equivalent to 350,000,000 years.
Therefore, it would take 350 million years for two continents
that are 3500 kilometers apart to collide.
<span>
To add, </span>a phenomenon of the plate tectonics of Earth that occurs at
convergent boundaries is called the continental collision.
A) a mouse, to an order of magnitude = 0.1 m ( a tenth of a meter ) That would be a big mouse but the alternatives are 1 meter or one hundredth of a meter... so go with 1/10th
<span>b) Easy = 1 meter </span>
<span>c) two choices 10m or 100 m . Go with 100 m </span>
<span>d) Stretch it out , trunk tip to tail tip - call it 10 m </span>
<span>e) Your choice 100 m or 1000 m..... These are estimates. So long as you are within one order of magnitude you can't really be given wrong. So I'd say 100m</span>
To solve this problem we will apply the concept of wavelength, which warns that this is equivalent to the relationship between the speed of the air (in this case in through the air) and the frequency of that wave. The air is in standard conditions so we have the relation,
Frequency 
Speed of sound in air 
The definition of wavelength is,

Here,
v = Velocity
f = Frequency
Replacing,


Therefore the wavelength of that tone in air at standard conditions is 0.589m