Show:
Rotational Motion
Gravity
Projectiles
Satillite Motion
Various
100
What is the difference between tangential speed and rotational speed?
Tangential speed is linear-has to do with distance and rotational speed is angular-has to do the number of rotations or revolutions per unit of time.
100
Where do you weigh more - the bottom of Death Valley or the top of a mountain?
bottom of Death Valley
100
What is a projectile?
Any object that moves through the air or through space under the influence of gravity.
100
Why do we launch our satellites above Earth's atmosphere?
To be nearly free of air resistance.
100
For orbits of greater altitude, is the period longer or shorter?
Longer
200
What is the relationship between tangential speed and distance from the center of the rotational axis?
Tangential speed increases as the distance from the center of the rotational axis increases.
200
How does the force of gravity change between two bodies when the distance between them is doubled?
The force of gravity decreases.
200
How can a projectile "fall" around the Earth?
Its tangential velocity (speed) must match the Earth's curvature so it falls around the Earth rather than into it.
200
Why doesn't the force of gravity change the speed of a satellite in circular orbit?
Gravity pulls straight downward with no component of force acting forward or backward.
200
If you toss a stick into the air, it appears to wobble all over the place. Specifically, what place?
center of mass (gravity)
300
What is the torque produced by a 40-N perpendicular force at the end of a 0.4 m-long wrench?
100 Nm
300
What is a black hole?
A concentration of mass resulting from gravitational collapse, near which gravity is so intense that not even light can escape.
300
What is the speed a projectile must maintain in order to "fall" around the Earth?
8 km/s
300
How far up must we launch our satellites to be above the Earth's atmosphere?
150 km
300
When is your weight equal to mg?
when there is no acceleration
400
What are the two things rotational inertia depends upon?
mass and how the mass is distributed about the axis of rotation
400
Distinguish between spring and neap tides, including when they occur.
Spring tides are high or low tides that occur when the Sun, Earth, and Moon are all lined up so that the tides due to the Sun and Moon coincide, making the high tides higher than average and the low tides lower than average. Neap tides occur when the Moon is midway between new and full and the pull of the Sun and Moon partly cancel each other making high tides lower than average and low tides higher than average.
400
A projectile is launched at an angle of 75* from the horizontal and strikes the ground a certain distance downrange. For what other angle of launch at the same speed would this projectile land just as far away?
15*
400
Explain how gravity changes the speed of a satellite in elliptical orbit.
Gravity slows the satellite to where it no longer moves farther from the Earth then it "falls" toward Earth, gaining the speed it lost.
400
What is the Newtonian synthesi?
The union of terrestrial laws and cosmic laws.
500
What is tension in a horizontal string that whirls a 2-kg toy in a circle of radius 2.5 m when it moves at 3 m/s neglecting air resistance?
7.2 N
500
What is the Newtonian synthesis?
The union of terrestrial laws and cosmic laws.
500
A projectile falls beneath the straight-line path it would follow if there were no gravity. How many meters does it fall below this line if it has been traveling for 1 second?
5 m
500
What did Kepler discover about the periods of planets and their distances from the sun?
The square of the orbital period is directly proportional to the cube of the planet's average distance from the sun.
500
Why is kinetic energy a constant for a stalellite in circular orbit but not for a satellite in an elliptical orbit.
For a satellite in circular orbit, no component of force acts along the direction of motion causing the speed, and thus the KE, to not change. In an elliptical orbit, a component of force exists along the direction of the satellite's motion due to gravity's pull. This component changes the speed and thus the KE.