Answer:
The work could be either positive or negative, depending on the direction the object moves
Explanation:
<span>a driver's foot off the accelerator and on the break pedal. C</span>
From Newton's second law of motion, it is identified that the net force applied to the object with mass m, will make it move with an acceleration of a. This can be mathematically translated as,
F = m x a
To solve for the mass of the sled, we derive the equation above such that,
m = F / a
Substituting,
m = (18 N) / (0.39 m/s²)
m = 46.15 kg
Then, we add to the calculated mass the mass of the extra material.
total mass = 46.15kg + 4.5 kg
total mass = 50.65 kg
We solve for the normal force of the surface to the object by calculating its weight.
F₂ = (50.65 kg)(9.8 m/s²)
F₂ = 496.41 N
The force that would allow barely a movement for the object is equal to the product of the normal force and the coefficient of kinetic friction.
F = (F₂)(c)
c = F/F₂
Substituting,
c = 18 N/496.41 N
c = 0.0362
<em>ANSWER: c = 0.0362</em>
