The spring constant is computed by:
F = kx
Where: F is the force applied in newtons (N)
k is the spring constant measured in newtons per meter (N/m); and
x is the distance the spring is stretched (m)
and
F = mg
Where: F is the force pulling objects in the direction of the Earth.
m is the mass of the object.
g is the acceleration due to gravity;
So plugging our values in the formula:
F = mg
= (1.8) (9.81) = 17.658N
k =
F/x = 17.658 /0.09 = 196.2 N/meter
Answer:
The mass of the planet is 
Explanation:
Given that,
Time period = 42 hours = 151200 sec
Orbital radius = 0.002819 AU = 421716397.5 m
Mass of moon 
We need to calculate the mass of the planet
Using Kepler’s third law


Where, a = orbital radius
T = time period
G = gravitational constant
M = mass of moon
m = mass of planet
Put the value into the formula





Hence, The mass of the planet is 
In my opinion, the answer is D, bc a vector is <span>a quantity having direction as well as magnitude, especially as determining the position of one point in space relative to another. Therefore giving the direction and speed. hope this helps, have a nice day :)</span>
The basic formula for power is P=W/t meaning it is the rate at which work is accomplished.