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a 4 kg block is being pulled by a string at a constant speed on a surface with coeficient of kinetic friction of .3. If the str...Question
a 4 kg block is being pulled by a string at a constant speed on a surface with coeficient of kinetic friction of .3. If the string is at an angle 45 degrees above the horizontal, what is the magnitude of the force F(also known as the string)?
Answers
Henry
Wb = m*g = 4kg * 9.8N/kg = 39.2 N. = Wt.
of block.
Fb = 39.2N @ 0o = Force of block.
Fp = 39.2*sin(0) = 0 = Force parallel to
surface.
Fv=39.2*cos(0)-Fap*sin45=39.2-0.707Fap.
= Force perpendicular to surface.
Fap*cos45-Fp-Fk = ma.
0.707Fap-0-0.3(39.2-0.707Fap)=ma=m*0=00.
0.707Fap - 11.76 + 0.212Fap = 0
0.92Fap = 11.76
Fap = 12.8 N. = Force applied.
of block.
Fb = 39.2N @ 0o = Force of block.
Fp = 39.2*sin(0) = 0 = Force parallel to
surface.
Fv=39.2*cos(0)-Fap*sin45=39.2-0.707Fap.
= Force perpendicular to surface.
Fap*cos45-Fp-Fk = ma.
0.707Fap-0-0.3(39.2-0.707Fap)=ma=m*0=00.
0.707Fap - 11.76 + 0.212Fap = 0
0.92Fap = 11.76
Fap = 12.8 N. = Force applied.