Mykola V. answered • 11/24/12
Math Tutor - Patient and Experienced
Since we're not dealing with any vertical components we can solve this linearly without resorting to trigonometric functions.
(a) The force of friction (Ff) is equal to the normal force (FN) multiplied by the coefficient of friction (μ). The equation looks like this:
Ff=FN*μ
To find FN, we simple calculate the Fg (force of gravity) and negate it because the normal force is equal to the force of gravity and acts upward so there's no vertical movement of the crate. Our equation for Fg is:
Fg=mg; where m is the mass of the crate and g is the acceleration due to gravity.
Fg=60kg*9.81m/s2
Fg=588.6N so FN=-588.6N
We plug back in for the Ff equation to get:
Ff=-588.6N*0.30
Ff=-176.6N
(b) To figure out the magnitude of acceleration we need the total force being applied to the crate. This is done by adding Ff and Fa.
FT=-176.6N+270N
FT=93.4N
Lastly, to figure out the acceleration we must take out the kg part of N by dividing FT by m.
a=FT/m
a=93.4N/60kg
a=1.56m/s2
I hope this helped!
Taliyah H.
Thanks it really did help. I wouldn't be posting so many questions but my Physics' teacher he doesn't really know how to teachh.
11/24/12