Question 12 (3 points) The diagram below shows four objects in the solar system which have equal masses.
1
3
4
2.
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Which of these pairs of objects exerts the least gravitational force on each other? (3 points)
Оа
Ob
Object 1 and Object 3
Object 4 and Object 3
Object 1 and Object 2
Ос
Od
Object 4 and Object 2

What is the measurement of how fast an object moves relative to a reference point?

An ionic compound can conduct electricity when a it is dissolved in water b its crystals are ground into powder c it is in solid form d it is heated to just below its melting point

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".