If a spacecraft in earth orbit is pushed by a thruster what will happen? a. the space craft will not move because it only works on earth. b. the spacecraft will change motion and will maintain this new orbit until the thruster is fired again. c. the spacecraft will move and then slowly come to a stop on its own. d. the spacecraft will not move due to air resistance.

Given the position vector of the particle r(t)=(t+1)i+(t^2−1)j+2t k, find the particle's velocity and acceleration vectors at t=1

Immediately upon reaching its lowest point, a falling pendulum bob has its greatest amount of energy, which is the initial amount of potential energy. a. heat; less than b. heat; more than c. kinetic; less than d. kinetic; more than

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".