# Nt1310 Unit 3

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Unit 3: Lesson 9

29) The earth has a mass of 5.98 x 1024 kg and the moon has a mass of 7.35 x 1022 kg. The distance from the centre of the moon to the centre of the earth is 3.84 x 108 m. A rocket with a total mass of 1200 kg is 3.0 x 108 m from the centre of the earth and directly in between the earth and the moon. Find the net gravitational force on the rocket from the earth and the moon.

Assume earth is mass 1, moon is mass 2, and rocket is mass 3.
Since the rocket (mass 3) is between the earth and the moon, the earth and the moon will attract the rocket in opposite directions. For that reason:

G = 6.67 x 10-11 Nm2/kg2
M1 = 5.98 x 1024 kg
M2 = 7.35 x 1022 kg
M3 = 3.0 x 108 kg
R from Earth to Moon = 3.84 x 108 m
R from Earth to Rocket
38) What type of charge is on the sphere? Explain your reasoning.

Since the plates are separated with negative on top and positive on the bottom, the sphere is positive charged to counter the force of gravity that would normally push it down.

b) What is the magnitude of the charge on the sphere?

The magnitude of the charge on the sphere is.

c) How many excess or deficit electrons does the sphere have?

The sphere has a deficit of three electrons, since the charge is positive.

Lesson 12:

39) A magnetic field of 0.0200 T [up] is created in a region. Find the initial magnetic force on an electron initially moving at 5.00 x 106 m/s [N] in the field.

First, determine the magnitude of the force:

This is an electron therefore it is negatively charged: using the left-hand rule, the fingers will point up and the thumb will point north therefore the palm will push west.

1.6 x 10-14 W

b) What is the radius of the circular path? Make a sketch showing the path of the electron

The electron will move with uniform circular