Answer:
<em>Answer: (A) 0.75 m/s^2</em>
Explanation:
The Second Newton's law states that an object acquires acceleration when an external unbalanced net force is applied to it.
That acceleration is proportional to the net force and inversely proportional to the mass of the object.
It can be expressed with the formula:

Where
Fn = Net force
m = mass
The ice skater pushes against a wall with a force of 59 N. The wall returns the force and the skater now has a net force of Fn=59 N that makes him accelerate. Being m=79 kg the mass of the skater, the acceleration is:


Answer: (A) 0.75 m/s^2
Given Information:
Mass of sock = 0.23 kg
Stretched length of sock = x = 2.54 cm = 0.0254 m
Required Information:
Spring constant = k = ?
Answer:
Spring constant = k = 88.82 N/m
Explanation:
We know from the Hook's law that
F = kx
Where k is spring constant, F is the applied force and x is length of sock being stretched.
k = F/x
Where F is given by
F = mg
F = 0.23*9.81
F = 2.256 N
So the spring constant is
k = 2.256/0.0254
k = 88.82 N/m
Therefore, the spring constant of the sock is 88.82 N/m
Answer: 1) a = 9.61m/s² pointing to west.
2) (a) Δv = - 37.9km/s
(b) a = - 6.10⁷km/years
Explanation: Aceleration is the change in velocity over change in time.
1) For the plane:


a = 9.61m/s²
The plane is moving east, so velocity points in that direction. However, it is stopping at the time of 13s, so acceleration's direction is in the opposite direction. Therefore, acceleration points towards west.
2) Total change of velocity:


km/s
The interval is in years, so transforming seconds in years:
v = 
km/years
Calculating acceleration:


Acceleration of an asteroid is a = -6.10⁷km/years .