Two particles a and b, move with constant velocities →v1 and →v2. at the initial moment their position vectors are →r1 and →r2 respectively. the condition for particles a and b for their collision is :

(1)vector r1 - vector r2 = vector v1 - vector v2

(2)vector r1 - vector r2/magnitude of (vector r1 - vector r2 ) = vector v1 - vector v2/ magnitude of (vector v1 - vector v2)

(3)vector r1 . vector v1 = vector r2 . vector v2

(4)vector r1 x vector v1 = vector r2 x vector v2

Afaulty model rocket moves in the xy-plane (the positive y direction is vertically upward). the rocket's acceleration has components ax(t) = ? t2 and ay(t) = ? ? ? t, where ? = 2.50 m/s4 , ? = 9.00 m/s2 , and ? = 1.40 m/s3 . at t = 0 the rocket is at the origin and has velocity ~v0 = v0x ? i + v0y ? j with v0x = 1.00 m/s and v0y = 7.00 m/s. (a) calculate the velocity and position vectors as functions of time. (b) what is the maximum height reached by the rocket? (c) sketch the path of the rocket. (d) what is the horizontal displacement of the rocket when it returns to y = 0?

This battery has a difference in potential energy between the positive terminal and negative terminal which units express this difference in energy

How many joules will be lost by 150 g of water if it is cooled from 90oc to 5oc?