9. The displacement is given by x = 2 t^2 + t + 5. The acceleration at t = 2 s is (a) 4 m/s2
(b) 8 m/s2
(c) 10 m/s2
(d) 15 m/s2

The sun’s mass is 2.0×10^ 30 kg, its radius is 7.0×10 5 km, and it has a rotational period of approximately 28 days. if the sun should collapse into a white dwarf of radius 3.5×10 3 km, what would its period be if no mass were ejected and a sphere of uniform density can model the sun both before and after?

In which of the following would the particles move most rapidly? a. ice at -20 °c b. water at 20 °c c. steam at 110 °c d. boiling water e. ice at 0 °c

Two balls, each with a mass of 0.5 kg, collide on a pool table. is the law of conservation of momentum satisfied in the collision? explain why or why not