D= Mass over Volume or M/V
and if needed m*d = V and vise versa
Answer:
(c) 10.29 J
(d) 113.19 J
(e) 113.19 J
(f) 10061 N/m
Explanation:
15 cm = 0.15 m
Let g = 9.8 m/s2
(c) The work done by gravitational force is the product of gravity force and the distance compressed

(d) By using law of energy conservation with potential energy reference being 0 at the maximum compression point. As the ball falls and come to a stop at the compression point, its potential energy is transferred to elastic energy, which is the work that the mattress does on the ball:


where h = 1.5 + 0.15 = 1.65 m is the vertical distance that it falls.

(e) Before the compression, the potential energy of the mattress is 0. After the compression, the potential energy is 113.19J. So it has increased by 113.19J due to the potential energy transferred from the falling ball.
(f) 


The answer is "the product of the object's moment of inertia and the object's angular velocity.
Explanation:
1) the diagonal force times the sine of the angle it makes will give you the vertical component or y component . use this to get the vertical components of all the diagonal forces . add all the vertical components as well as the vertical forces together
2) the diagonal force times the cosine of the angle it makes gives the horizontal component or x component. do this to get the x component of all the diagonal forces.
add all the x components as well as the horizontal forces together to get the final x component
3)using the triangle of vectors, the resultant force is calculated
sum of y component = 3.2N
sum of x component= 5.7N
resultant force = 6.5N