Hooke's law says that the force produced by a spring is proportional to the displacement (linear amount of stretching or compressing) of that spring:
F = -kx
where k is called the force constant or spring constant of the spring. Each spring has its own force constant.
The diagram defines all of the important dimensions and terms for a coil spring. For each mass hung on it (the mass could be zero), a spring has some natural length, at which it is neither compressed (shortened) or extended (lengthened). At that point, the upward force produced by the spring is exactly balancing the gravitational force on the mass and spring (remember that the spring itself has mass).
We define the coordinate x so that it is negative when the spring is compressed, zero at the natural length and positive when the spring is extended. The minus sign in F = -kx is there by convention; we think of F as the restoring force. When the spring is compressed, a positive force is required to extend it, and when it is extended, a negative force is required to shorten it, or restore it to its natural length.
If the spring is strong or stiff, k will be large, and k will be small for a weak spring.
Hooke's law is applicable not only to coil springs like the one shown here, but also to the bending of metal and some other materials, the stretching of wires like guitar strings, the stretching of rubber bands, and the stretching and compressing of chemical bonds.
Answer: Choice C) 10.5
The distance from A to C is 7 units (count out the spaces between the two points, or subtract y coordinates 4-(-3) = 4+3 = 7)
Let AC = 7 be the base of the triangle. You might want to rotate the image so that AC is laying horizontally rather than being vertical.
Now move to point P. Walk 3 spaces to the right until you land on segment AC. This shows that the height of the triangle is 3 when the base is AC = 7.
base = 7, height = 3
area of triangle = (1/2)*base*height
area of triangle = 0.5*7*3
area of triangle = 10.5 square units
Answer: 8.3 minutes
Step-by-step explanation:
1 mile is to 1.60934km so 93 million miles is:
= 93 * 1.609
= 149,637,000 km
Travelling at 300,000 km per second, the number of seconds it takes is:
= 149,637,000/300,000
= 498.79 secs
In minutes this is:
= 498.79/60
= 8.3 minutes
