Answer:
F = 9.81 [N]
Explanation:
To solve this problem we must use Newton's third le which tells us that the sum of forces on a body that remains static must be equal to one resulting from these forces in the opposite direction.
Let's perform a summation of forces on the vertical axis-y to determine the normal force N.
∑F = 0 (axis-y)

where:
m = mass = 4 [kg]
g = gravity acceleration = 9.81 [m/s²]
![N - (4*9.81)=0\\N = 39.24 [N]](https://tex.z-dn.net/?f=N%20-%20%284%2A9.81%29%3D0%5C%5CN%20%3D%2039.24%20%5BN%5D)
Now we know that the frictional force can be calculated using the following equation.
f = μ*N
where:
f = friction force [N]
μ = friction coefficient = 0.25
N = normal force = 39.24 [N]
Now replacing:
![f = 0.25*39.24\\f = 9.81[N]](https://tex.z-dn.net/?f=f%20%3D%200.25%2A39.24%5C%5Cf%20%3D%209.81%5BN%5D)
Then we perform a sum of forces on the X-axis equal to zero. This sum of forces allows us to determine the minimum force to be able to move the object in a horizontal direction.
∑F = 0 (axis-x)
![F-f=0\\F-9.81=0\\F= 9.81[N]](https://tex.z-dn.net/?f=F-f%3D0%5C%5CF-9.81%3D0%5C%5CF%3D%209.81%5BN%5D)
If the coefficient was smaller, a smaller force (F) would be needed to start the movement, this can be easily seen by replacing the value of 0.25, by smaller values, such as 0.1 or 0.05.
If the coefficient were larger, a larger force would be needed.
Answer:
Wind blowing across the surface eroded the limestone.
Explanation:
Answer:
Displacement from the starting position is 1224m
Explanation:
The object is moving at 120 meters per second, it does this for 10.2 seconds. Use multiplication to find the answer.

Answer:
The magnitude of the force net is an acting object multiplied by acceleration of the object
Answer:
1. The reason why nichrome wire is used in a heater is due to the properties of nichrome which makes it a material of choice for heating application including;
i) The cost of manufacture of nichrome is low
ii) Nichrome has both high mechanical and creep strength, and therefore is suitable for installation and use in a wide setting
iii) Nichrome has a high resistance to electron flow, making it a good electrical heating element
iv) Nichrome has a high resistance to oxidation, such that it can be reused several times as a heater
v) The high ductility of nichrome allows it to be stretched and drawn around different vessels with contents to which heat is to be supplied
2. Copper wire is not used in heaters because according to Joule's law, the heat produced from the flow of electric current, 'I', through a material having a resistance, 'R', for a time, 't', is proportional to I²·R·t, and copper has a very low resistance, 'R', to the flow of electric current, and therefore, will not produce sufficient heat required at a given current level
Explanation: