I really don’t know but I think it’s D
Answer:
<h2>
206.67N</h2>
Explanation:
The sum of force along both components x and y is expressed as;

The magnitude of the net force which is also known as the resultant will be expressed as 
To get the resultant, we need to get the sum of the forces along each components. But first lets get the acceleration along the components first.
Given the position of the object along the x-component to be x = 6t² − 4;


Similarly,



Hence, the magnitude of the net force acting on this object at t = 2.15 s is approximately 206.67N
Answer with Explanation:
We are given that
Mass of spring,m=3 kg
Distance moved by object,d=0.6 m
Spring constant,k=210N/m
Height,h=1.5 m
a.Work done to compress the spring initially=
b.
By conservation law of energy
Initial energy of spring=Kinetic energy of object



v=5.02 m/s
c.Work done by friction on the incline,

1) 29.4 N
The force of gravity between two objects is given by:

where
G is the gravitational constant
M and m are the masses of the two objects
r is the separation between the centres of mass of the two objects
In this problem, we have
(mass of the Earth)
(mass of the box)
(Earth's radius, which is also the distance between the centres of mass of the two objects, since the box is located at Earth's surface)
Substituting into the equation, we find F:

2) 
Let's now calculate the ratio F/m. We have:
F = 29.4 N
m = 3.0 kg
Subsituting, we find

This is called acceleration of gravity, and it is the acceleration at which every object falls near the Earth's surface. It is indicated with the symbol
.
We can prove that this is the acceleration of the object: in fact, according to Newton's second law,

where a is the acceleration of the object. Re-arranging,

which is exactly equal to the quantity we have calculated above.
I think metal, steel and copper.