quiz ?

The helicopter can produce a maximum downward air speed ( v = 24 m/s ) in a slipstream of a diameter ( D = 9 m). Knowning that the weight of the helicopter and the crew is ( 15 kN ) and assuming air density rho ( ρ = 1.21 kg/m^3 ), determine the maximum load that helicopter can lift while hovering in midair. ( 29.3 kN ) Thankyou.

A uniform cylinder...

A uniform cylinder (A) has a mass ( m = 3 kg ), radius ( r = 150 mm ), and can roll without sliding on a cart ( C ) of mass ( M = 5 kg ). Cylinder (A) is attached to a spring (AB) of stiffness (constant) k = 100 N/m as shown (attached). The system is released from rest when the spring is stretched ( Δx = 20mm ). Neglecting wheel friction, determine the velocity of the cart and the angular velocity of the cylinder when the spring first reaches its undeformed state.

Structural question

Base isolation technique has become the method of choice for structural design of buildings and bridges located in highly seismic areas in recent years. Please provide of an overview of this approach. Also, discuss the application of rolling type bearings for equipment isolation.