A bicycle tire is spinning counterclockwise at 4.00 rad/s. During a time period Δt = 2.10 s, the tire is stopped and spun in the opposite (clockwise) direction, also at 4.00 rad/s. Calculate the change in the tire's angular velocity Δ and the tire's average angular acceleration av. (Indicate the direction with the signs of your answers.) (a) the change in the tire's angular velocity Δ (in rad/s)
rad/s
(b) the tire's average angular acceleration av (in rad/s2)
rad/s2

Explain earth's motion, using the terms "precession" and "rotation" in your answer.

Match each vocabulary term to its definition. 1. electrons neutral subatomic particles found in the nucleus of the atom 2. neutron lowest energy position of an electron in an atom 3. photon the path of an electron around the nucleus of an atom 4. ground state negatively charged, subatomic particles 5. protons packet of energy of specific size 6. element substance with only one type of atom 7. orbital positively charged, subatomic particles found in the nucleus of the atom

Astone is dropped from the upper observation deck of a tower, 250 m above the ground. (assume g = 9.8 m/s2.) (a) find the distance (in meters) of the stone above ground level at time t. h(t) = (b) how long does it take the stone to reach the ground? (round your answer to two decimal places.) s (c) with what velocity does it strike the ground? (round your answer to one decimal place.) m/s (d) if the stone is thrown downward with a speed of 2 m/s, how long does it take to reach the ground? (round your answer to two decimal places.) s