Suggest and explain a reason why the brake blocks on a bicycle need to be replaced from time to time

Suppose you increase your walking speed from 7 m/s to 12 m/s in a period of 3 s. What is your acceleration?

What is one important characteristic that all Protists share that makes them different from bacteria?

A 7.0 kg bowling ball traveling at 2.0 m/s collides with a stationary 0.5 kg beach ball in an elastic collision. The bowling ball leaves the collision with a velocity of 1.5 m/s traveling in the same direction as the beach ball.

Energy that is 'lost" to heat, has merely been converted to another form, not lost forever.

An element's atomic number is 45. How many protons would an atom of this element have?

The sun is the centermost star of our solar system. a. True b. False

When an electron moves from a lower to a higher energy level

Which of the following is all matter made of? A. Hot particles B. Cold particles C. Constantly moving particles D. Nonmoving particles

Which of the following has longest wavelength, a) blue light b) red light c) x-rays d) gamma rays?

are the properties of a specific element the same as the properties of a molecule made up of that element? why or why not