When 150 joules of work is done on a system by
an external force of 15 newtons in 20. seconds,
the total energy of that system increases by
(1) 1.5 x 10
(3) 3.0 x 10)
(2) 2.0 x 10-
(4) 2.3 x 103]

The heliocentric and the geocentric models of the solar system included these central principles

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".

At what time would the magnitude of the velocity reach 36.00 km/hr