Aconverging lens (l) of focal length f =40 cm, gives for an object ab placed at a distance d from (l) an image a’b’ we give successively to d the following value 10cm indicate with justification the value of a’b’

The membrane surrounding a living cell consists of an inner and an outer wall that are separated by a small space. assume that the membrane acts like a parallel plate capacitor in which the effective charge density on the inner and outer walls has a magnitude of 7.0 × 10-6 c/m2. (a) what is the magnitude of the electric field within the cell membrane? (b) find the magnitude of the electric force that would be exerted on a potassium ion (k+; charge = +e) placed inside the membrane.

Transfer chemicals from one location to another to weather objects. a-water b-physical weathering c-chemical weathering

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •