Suppose you have a mass of 70 kg and are currently standing on one end of a 10 m

Question

Suppose you have a mass of 70 kg and are currently standing on one end of a 10 meter long, 1 meter high platform (which has a mass of 46 kg). The coefficients of friction between your feet and the platform are µ_k=0.9, µ_s=1.1, and the coefficients of friction between the platform and the ground are µ_k=0.09, µ_s=0.12. Suppose you run as fast as possible towards the far end of the platform (accelerating at as great a rate as friction will allow). If you run straight off the edge of the platform, how far away from the platform will you be when you land?

Explanation / Answer

Maximum frictional force between me and platform = uk*Mg

= 0.9*70*9.8 N

Acceleration of mine =uk g = 0.9*9.8 m/s^2

Acceleration of the platform = - (Friction Force from me-friction from ground)/m

= - (0.9*70*9.8-0.09*(70+46)*9.8)/46 = - 11.2 m/s^2

time to cover the platform t = sqrt(2s/a)

= sqrt(2*10/(11.2+0.9*9.8)) = 1 s

My speed before jumping = at = 0.9*9.8*1 = 8.82 m/s

time taken to fall = sqrt(2h/g) = sqrt (2*1/9.8) =0.4518 s

Range of falling = 8.82*0.4518

= 3.985 m answer

Related Questions

Navigate

• Browse (All)
• Browse S
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.