It's important to know how much force actually produces acceleration.
By factoring in friction, we can compute the net acceleration, which helps us accurately calculate the motion of objects!
When friction is involved, the actual net acceleration can be calculated by subtracting the frictional force from the total force:
Problem: What is the acceleration if \( F = 60\,\text{N} \), \( m = 5\,\text{kg} \), \( \mu = 0.2 \), and \( g = 9.8\,\text{m/s}^2 \)?
Solution:
\( \mu m g = 0.2\cdot 5\cdot 9.8 = 9.8\,\text{N} \)
\( F_\text{net} = 60 - 9.8 = 50.2\,\text{N} \)
\( a = \dfrac{F_\text{net}}{m} = \dfrac{50.2}{5} = 10.04\,\text{m/s}^2 \approx \mathbf{10.0\,\text{m/s}^2} \)
A box with a mass of 5 kg is pulled across a horizontal surface by a force of 60 N. The coefficient of friction between the box and the surface is 0.2.
What is the net acceleration?
SCORE:
If you don't move forward while crossing the road, you'll remain stationary — mirroring the natural tendency of objects at rest, exactly as Newton's First Law (Inertia) describes.
When you sprint across the busy street, the acceleration you achieve depends on the force you apply relative to your mass, just like Newton's Second Law.
During collisions, every push you deliver is met with an equal push back from the car, perfectly illustrating Newton's Third Law of Motion.