A 24.8 cm tall object is placed in front of a lens, which creates a
-3.09 cm tall image. What is the
magnification?
(Mind your minus signs.)
(Unit = cm)
(all the other answer are wrong)

An object has a weight of 500 on earth what is the mass of this object

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?

Why do astronauts in the space shuttle weigh less?