A 38 kg child is sitting on a slide at angle 45o from the horizontal. What is the minimum value of static friction between the child and the slide that prevents the child from sliding down?

Answer 1

Wc = m*g = 38kg * 9.8N/kg = 372.4 N. =
Wt. of child.

Fc = 372.4 N. @ 45o. = Force of child.
Fp = 372.4*sin45 = 263.3 N. = Force
parallel to slide.
Fv = 372.4*cos45 = 263.3 N. = Force
perpendicular to slide.

Fs = Force of static friction.

Fp-Fs = m*a.
372.4 - Fs = 38*0 = 0
Fs = 372.4 N. = Min.static friction.

Answer 2

Correction:
Fp-Fs = m*a
263.3 - Fs = 38*0 = 0
Fs = 263.3 N.=Force of static friction.