<span>The answer of these two problems are :
A) a = (F-W)/m = (100-500)/500/g = 9.8*500/500 = +9.8
m/sec^2
B) a1 = +9.8-g = 0</span>
The Young modulus is given by:

where
F is the force applied

is the initial length of the wire

is the cross-sectional area of the wire

is the stretch of the wire
The wire in the problem stretches by

of its length, this means

We can also calculate the area of the wire; its radius is in fact half the diameter:

and so the area is

We know the force applied to the wire, F=20 N, so now we have everything to calculate the Young modulus:
Point X lies on a horizontal line. We can intuitively say that the slope of the graph at point X is 0, therefore the acceleration at point X is 0m/s²
Point Y lies on a downward slanting line. To calculate the slope of that line, let's apply this equation:
m = (y₂-y₁)/(x₂-x₁)
m = slope, (x₁, y₁) and (x₂, y₂) correspond to the coordinates of the line's endpoints.
Given values:
(x₁, y₁) = (7, 5)
(x₂, y₂) = (12, 0)
Plug in and solve for m:
m = (0 - 5)/(12 - 7)
m = -1
The acceleration at point Y is -1m/s²
Choice A
To answer this question, we will use the law of conservation of momentum which states that:
(m1+m2)Vi = m1V1 + m2V2 where:
m1 is the mass of the woman = 50 kg
m2 is the mass of the cart = 10 kg
Vi is the initial velocity (of woman and cart combined) = 5 m/sec
V1 is the final velocity of the woman = 7 m/sec
V2 is the final velocity of the cart that we need to calculate
Substitute with the givens in the above equation to get the final velocity of the cart as follows:
(50+10)(5) = (50)(7) + (10)V2
10V2 = -50
V2 = -5 m/sec
Note that the negative sign indicates that the cart is moving in an opposite direction to the others.
Answer:
On a velocity-time graph… slope is acceleration. the "y" intercept is the initial velocity. when two curves coincide, the two objects have the same velocity at that time.