What's phase changes mean? I can't find it

A woman on a bicycle travels at 9 m/s relative to the ground as she passes a little boy on a tricycle going in the opposite direction.

Julie is cycling at a speed of 3.4 meters/second. If the combined mass of the bicycle and Julie is 30 kilograms, what is the kinetic energy? A. 1.7 * 102 joules B. 1.5 * 102 joules C. 2.0 * 102 joules D. 2.2 * 102 joules

Which of the following will attract one another? A. The north pole of magnet and the south pole of another magnet B. The north pole of a magnet and the north pole of another magnet C. The south pole of a magnet and the south pole of another magnet D.

Sarah's mom takes a parkway to work. It takes her 30 minutes to travel from mile marker 88 where she enters to her exit at mile marker marker 121. What is her average speed?

A block of metal has a width of 3.2 cm, a length of 17.1 cm, and height of 3.8 cm. its mass is 1.3 kg. calculate the density of the metal. express your answer to two significant figures and include the appropriate units.

In deep space there is very little friction once they are launched into a probe into deep space where there are no external forces acting on it scientists shut the probe's engines off because the scientists want the probe to

What topic in a biology textbook is directly related to physics

A soccer ball player bounces the ball off her head, changing the velocity of the ball. She changes the x-component of the velocity of the ball from vix = 7.9 m/s to vfx = 5.9 m/s and the y-component from viy = - 3.4 m/s to vfy = 4.5 m/s.

Do you think an observer on another planet in the solar system might see eclipses

A. A vector is any element of a vector space. Is this statement true or false? A. True by the definition of a vector space B. False; not all vectors are elements of a vector space. C. False; a vector space is any element of a vector.