Question

How much force is needed to lift a 10.0 kg mass from a horizontal position using
the human arm if the forearm is 25 cm long and the lifting muscle is 2.0 cm from
the elbow?

Answer 1

50481, Physics, Mechanics — Kinematics — Dynamics

Question How much force is needed to lift a 10.0 kg mass from a horizontal position using the human arm if the forearm is 25 cm long and the lifting muscle is 2.0 cm from the elbow?

Solution Using lever rule we can find:

$F_{1}L_{1}=F_{2}L_{2}$

$F_{2}=F_{1}\frac{L_{1}}{L_{2}}=mg\frac{L_{1}}{L_{2}}=10\cdot 9.8\frac{25}{2}1225\,N$

So it is needed 1225 N to lift a 10.0 kg mass.