Needed! determine the mechanical energy of this object: a 1-kg ball rolls on the ground at 2 m/s.
a. the ball is on the ground, so the mechanical energy is zero.
b. 2 j
c. 1 j
d. 4 j

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

We have a colorless transparent liquid. it looks like water. we seperated it into a solid and a liquid by evaporration and condention was this a chemichal or a physical seperation a. chemical seperation b. physical seperation

Select all the correct answers. which changes will increase the rate of reaction during combustion? decreasing the area of contact between the reactants adding more oxygen to the reaction removing heat from the reaction changing the reactants from solid form to powdered form lowering the exposure of the reactants to air