Warmup: Finish #4 and #5

Planet Orbital Period

Orbital Radius (AU)

Mercury 0.241 0.387

Venus 0.615 0.723

Earth 1 1

Moon 0.0748

Mars 1.881 1.524

Jupiter 11.86 5.203

Saturn 29.46 9.529

Uranus 84.32 19.19

Neptune 164.8 30.06

Pluto 248.1 39.53

1) Try to determine the formula for the ratio of the average orbital radius to the orbital period. Use a scatterplot to help you do this.

2) Should Kepler’s Law apply in the same way to the Moon? Does it? Why or why not?

3) If the amount of sunlight striking an object obeys an inverse-square law, how much less sunlight per square meter does Pluto get than Earth? How much more sunlight per square meter does Mercury get?

4) If it takes light travelling at a velocity of 3 x 108 m/s 8 minutes to get to Earth, how many meters is 1 AU?

5) If the mass of the Sun is 2 × 1030 kg, and the mass of Earth is 6 x 1024 kg, what is the force exerted by the sun?

Practice Quiz Answers

1) A2) C3) A,b,c4) More5) More6) Less7) C8) False; very tiny number, weak force9) False; difficult but possible to measure10) False; law calculatse how much they attract, theory attempts to explain why11) E; they perceive no weight due to no normal force

14) False15) False16) False17) False18) False19) False20) False

M1 M2 r F60 60 1 2.4012E-0760 5.98E+24 6370000 589.7960 1.196E+25 6370000 1179.5960 5.98E+24 3180000 2366.660 5.98E+24 6470000 571.760 1.2E+22 1150000 36.3160 1.901E+27 6980000 156152.29

G6.67E-11

M1 r g5.98E+24 6370000 9.835.98E+24 6480000 9.55.98E+24 42300000 0.22

1.2E+22 1150000 0.611.901E+27 6980000 2602.54