So I need help I haft to calculate the speed velocity and acceleration of two vehicles on going at a constant speed at 30 km/h and the second going also at a constant speed but 60 km\h relative to the first car please help

Density of salty water as compared to the density of pure water is(a) is less(b) is always equal(c) is always more(d) may be less or more

Ais useful when you need a simple machine to you separate two things. a. lever b. screw c. pulley d. wedge

Aperson stands on a platform, initially at rest, that can rotate freely without friction. the moment of inertia of the person plus the platform is ip. the person holds a spinning bicycle wheel with its axis horizontal. the wheel has moment of inertia iw and angular velocity ωw. take the ωw direction counterclockwise when viewed from above. part a what will be the angular velocity ωp of the platform if the person moves the axis of the wheel so that it points vertically upward?