To solve this problem it is necessary to apply the concepts related to Hooke's Law as well as Newton's second law.
By definition we know that Newton's second law is defined as

m = mass
a = Acceleration
By Hooke's law force is described as

Here,
k = Gravitational constant
x = Displacement
To develop this problem it is necessary to consider the two cases that give us concerning the elongation of the body.
The force to keep in balance must be preserved, so the force by the weight stipulated in Newton's second law and the force by Hooke's elongation are equal, so

So for state 1 we have that with 0.2kg there is an elongation of 9.5cm


For state 2 we have that with 1Kg there is an elongation of 12cm


We have two equations with two unknowns therefore solving for both,


In this way converting the units,


Therefore the spring constant is 313.6N/m
Answer: sorry mate but what's the question here tho?
Explanation:
My Van de Graaff generator will create sparks about 10 to 12 inches in length. I like to charge myself on it and point at the aluminum blinds on the window. The charge (electronic wind) will cause the blinds to move. I can do this from about 8 feet away with ease. Soap bubbles are also interesting to play with around the Van de Graaff generator. They initially are attracted to the Van de Graaff generator and float toward it; once they become charged by the Van de Graaff generator, they float away due to repulsion. There are multitudes of fun things you can do with your Van de Graaff generator. Use your imagination!
Answer:
(a) t = 0 s
(b) t = 0 s, 30 s, 55 s
(c) t = 40 s to t = 60 s
(d) t = 10 s to t = 15 s
(e) a = 6 m/s^2
Explanation:
(a) The car is at starting position at t = 0 s and v = 0 m/s.
(b) The velocity of car is zero when the time is t = 0 s, 30 s and 55 s.
(c) from t = 40 s to 60 s the car is moving in the negative direction.
(d) The fastest speed is 60m/s from t = 10 s to t = 15 s.
(e) The slope of the velocity time graph gives acceleration.
a = (60 - 0) / (10 - 0) = 6 m/s^2