Young david who slew goliath experimented with slings beforetackling the giant. he found that he could revolve a sling oflength 0.600 m at the rate of9.00 rev/s. if he increased the lengthto 0.900 m, he could revolve the slingonly 7.00 times per second.

(a) what is the speed of the stone for eachrate of rotation?
1 m/s at 9.00 rev/s
2 m/s at 7.00 rev/s

(b) what is the centripetal acceleration of the stone at9.00 rev/s?
3 m/s2

(c) what is the centripetal acceleration at 7.00 rev/s?
4m/s2

a) v1 = 33.9 m/s , v2 = 39.6 m/s, b) a = 1015.4 m/s² and c)  a = 1742.4 m/s²

Explanation:

To solve this exercise we will use the relationship between angular and linear quantities

a) The angular and linear velocity are related by

     v = w r

Let's reduce the quantities to the SI system

    w1 = 9.00 rev / s (2π rad / 1rev) = 18 π rad / s = 56.55 rad / s

    w2 = 7.00 rev / s = 14π rad / s = 43.98vrad / s

     v1 = 56.55 0.6

     v1 = 33.9 m / s

     v2 = 43.98 0.9

    v2 = 39.6 m / s

b) centripetal acceleration for v1

     a = v² / r

     a = 33.9² / 0.6

     a = 1015.4 m / s²

c) centripetal acceleration for v2

     a = 39.6² / 0.9

     a = 1742.4 m / s²

explanation:

earth's surface is mainly heated by the absorption of infrared radiation from the sun.

evaporation occurs because molecules in liquid water are warmed ( usually by the sun) and vibrate quicker, becoming less dense and rise.

condensation occurs because molecules in water vapor are cooled and therefore vibrate more slowly thus becoming more dense and eventually fall to earth.

lines of equal barometric pressure on a weather map are called: isobars : lines of equal temp on a weather map are called: isotherms.​

c

explanation: