1. a certain cd has a playing time of 74 minutes. when the music starts, the cd is rotating at an angular speed of 4.70×10(2) revolutions per minute (rpm). at the end of the music, the cd is rotating at 2.40×10(2) rpm. find the magnitude of the average angular acceleration of the cd. express your answer in rad/s².
2.the pedals of a bicycle rotate in a circle with a diameter of 40 cm. what is the maximum torque a 64-kilogram rider can apply by putting all of her weight on one pedal?

1.

Explanation:

Initial angular speed of the CD is given as

Similarly final angular speed is given as

now angular acceleration is given as

2.

Explanation:

As we know that torque is the product of force and its distance from the axis of rotation

so we will have

so we have

now we have

the results is a decrease in air temperature with an increase of altitude.

explanation:

answer: 802.3 kilo joules of energy represents 191.75 kilo calorie of energy.

explanation:

energy released during combustion of one mole methane = 802.3 kilo joules

if 1 kilo joule = 0.239006   kilo calorie

then ,802.3 kilo joule will be = 802.30.239006 kilo calorie

802.3 kilo joule = 191.75 kilo calorie

hence, the energy in kilo calorie is 191.75 kilo calorie.