Hooke's Law
F = k. Δx
Δx = 30 cm = 0.3 m
200 = k . 0.3

the spring stretch for 100 N:

Answer:
a) 1504.8 J
b) 991.76 J
c) 0J
d) 0J
Explanation:
(a) The work done by the force P on the box is given by the following formula:

P: applied force = 171N
x: distance in which the for P is applied = 8.80m
you replace the values of P and x and obtain:

(b) The work don by the friction force is:

μ = coefficient of kinetic friction = 0.250
M: mass of the box = 46.0kg
g: gravitational constant = 9.8 m/s^2

(c) The Normal force is

but this force does not do work on the box because the direction is perpendicular to the direction of the force P.

(d) the same as before:

Answer:
1270 J
Explanation:
Recall that the mechanical energy of a system is the addition of the Potential energy and the Kinetic energy at any given time.
As the skier descends, potential energy is converted into kinetic energy, but the total mechanical energy should remain the same.
We see that it is not the case, so that difference is what has gone into thermal energy; 19500 J - 18230 J = 1270 J
Answer:
Silage can be made by one or more of the following methods: placing cut green vegetation in a silo or pit; piling the vegetation in a large heap and compressing it down so as to purge as much oxygen as possible, then covering it with a plastic sheet; or by wrapping large round bales tightly in plastic film.
Explanation: