Which of the following is a clue of a chemical change?
a. iron changes color when heated
b. gas bubbles form in boiling water
c. balls of wax form when melted wax is poured into ice water
d. a gas forms when vinegar and baking soda are mixed

•• al and bert are jogging side-by-side on a trail in the woods at a speed of 0.75 m/s. suddenly al sees the end of the trail 35 m ahead and decides to speed up to reach it. he accelerates at a constant rate of 0.50 m/s2, while bert continues on at a constant speed. (a) how long does it take al to reach the end of the trail? (b) once he reaches the end of the trail, he immediately turns around and heads back along the trail with a constant speed of 0.85 m/s. how long does it take him to meet up with bert? (c) how far are they from the end of the trail when they meet?

The rocket is fired vertically and tracked by the radar station shown. when θ reaches 66°, other corresponding measurements give the values r = 32700 ft, r¨ = 85 ft/sec2, and θ˙ = 0.019 rad/sec. calculate the magnitudes of the velocity and acceleration of the rocket at this position.

Which best describes what forms in nuclear fission? a. two smaller, more stable nucleib. two larger, less stable nucleic. one smaller, less stable nucleusd. one larger, more stable nucleus