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Terms to Know
Solving
100

What is the condition that causes an object to rotate around its axis?

Torque

100

A June bug is clinging to the rim of a 26.7 cm radius bicycle wheel.   The wheel is rotating at 11.75 rad/s.  The Bicycle wheel then accelerates uniformly at -1.70 rad/s2 for 5.40 seconds.

A. Which direction is the wheel rotating?

B. What was the wheel's final angular velocity?

C. How many revolutions (angular displacement) does the wheel rotate through during the acceleration?


D. How far has the June bug traveled around the rim of the wheel?

A. Counterclockwise

B. wf= 2.57 rad/s

C. 6.15 revolutions

D. s= 10.3 meters

200

What force pulls an object in circular motion towards the center of motion (aka axis)?

Centripetal Force

200
A male goose (9.1 N) and a female goose sit on a 30.1 meter long seesaw.  The pivot point sits in the middle.  The male goose is on the end of the seesaw and the female goose is 25.1 meters away from the male goose.  What is the weight of the female goose?

13.0 N

300

What is rotational equilibrium? 

The point at which no rotational acceleration is occurring.  In this case the two torques that are affecting a system are equal.

300

A 2245 kg car drives around a curve of an off-ramp with a radius of 115 m.  The car takes the off-ramp at 24.6 m/s (linear) and barely keeps from sliding off the ramp.

What force is providing the centripetal force?


What is the coefficient of friction?

Friction


.536

400

What is the difference between circular and rotational motion?

Circular motion - moving in a circle around the center of a circle

Rotational motion -spinning around an axis, occurs on the edge of the circle

400

An astronaut (98.7 kg) is doing a spacewalk outside the International Space Station at an altitude of 409 km above the earth's surface.  Earth's radius is 6378 km and its mass is 5.972 * 1024 kg.

What is the astronaut's acceleration due to gravity?

What is earth's gravitational force due to gravity?

g = 8.653 m/s2

Fg = 854 N

500

Describe Kepler's three laws of planetary motion.

1st law - planetary orbits are elliptical with the sun

2nd law - planets travel faster near the sun

3rd law - the semi-major axis and the period of the planet's ellipse is proportional

500

Mars has two moons.  Phobos has a semi-major axis of 9377 km and a period of 7.66 hours.  If Deimos has an orbital period of 30.35 hours, what is its semi-major axis?

2.35 * 104 km