When a person stands on tiptoe on one foot (a strenuous position), the position of the foot is as shown in Figure P12.42a. The total gravitational force F S g on the body is supported by the normal force n S exerted by the floor on the toes of one foot. A mechanical model of the situation is shown in Figure P12.42b, where T S is the force exerted on the foot by the Achilles tendon and R S is the force exerted on the foot by the tibia. Find the values of T, R, and u when Fg 5 700 N.
Week 5 Physics 2 for Engineering Chapter 24: Capacitance and Dielectrics Capacitors store charge C = Q/V Unit is Farads, 1 Farad = 1 C/V Review: Q = σ A V = Ed Parallel Plate Capacitor C = A Ɛ / 0 C = Q/V = σ A/ Ed = A Ɛ / d 0 Capacitors in series Charge on each capacitor is the same Voltage on each capacitor is different Applied voltage is equal to the sum of voltages on the two capacitors (V = V +V ) 1 2 1/C eq1/C +11C 2 Capacitors in parallel Voltage (potential) on each capacitor is the same Charge on each capacitor is different (Q = Q +Q ) 1 2 C eq +C1 2 Energy stored in capacitor U= (1/2) Q