a) Force b) Inertia c) Unbalanced Force d) acceleration 5) The force that attracts a body toward the center of the earth a) force/acceleration b) Gravity c) Inertia d) Velocity 6) An object in motion stays in motion unless acted upon by another force. a) Friction b) Unbalanced Force c) 100m/s2 d) Mass 3) the measurement of an object's speed and direction a) Inertia b) 40 g c) Velocity d) Friction 4) The tendency of an object to resist change in motion. a) Friction b) Newton's 1st Law c) Mass d) force/acceleration 2) the tendency of resistance to motion of one object moving relative to another.