ASTRO 001 Lecture 1: ASTRO001 - Lecture 1 - Gravity and the Seasons Update

96 views2 pages

cerisegiraffe538

2 Nov 2017

School

PSU

Department

Astronomy and Astrophysics

Course

ASTRO 001

Professor

Jane Charlton

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Astro001 - lecture 1 - gravity and the seasons. An object at rest or in motion in a straight line at a constant speed will remain in that state unless acted upon by a force. Sun disappears = earth continues in direction it was travelling in its orbit when sun disappeared. Acceleration of a body due to a force will be in the same direction as the force, with a magnitude directly proportional to its mass. Smaller mass = increased acceleration if same force applied to it. Every action has an equal and opposite reaction. Sun exerts force on planets; planets exert equal force on sun but it only moves slightly bc of its large mass. Strength of gravity on the surface of a planet is (cid:0)= (cid:0)/(cid:0)2. M is the mass of the planet. Mass of planet a is twice that of planet b & both planets have the same.

Related Questions

1)The earth makes a gravitational force on the moon, and themoon makes a gravitational force on the earth. Which of theseforces is larger?
a)The gravitational force of the earth on the moon isgreater.
b)The gravitational force of the moon on the earth isgreater.
c)The two forces are equal.
d)There is no way to tell.
2) Suppose you could climb a ladder whose height is equal to theradius of the earth. At the top of this ladder
a) your weight would be the same as it is at the surface of theearth.
b)your weight would be Â½ its value at the surface of theearth.
c)your weight would be Â¼ its value at the surface of theearth.
d) you would be weightless.
3) The moon has potential energy because it is near the earth. Ifit were twice as far from the earth as it is now,
a) its potential energy would be higher than it is now.
b) is potential energy would be less than it is now.
c) its potential energy would be the same as it is now.
4) Suppose a satellite has a circular orbit around the earth. Whydoes it stay in orbit?

a)Because gravity does not act on it in the vacuum of space.
b)Because it is in equilibrium; the inward pull of gravity isbalanced by an outward force.
c) Because as it moves tangentially, the satellite is acceleratedby the force of gravity toward the center of the earth.

Which of the following statements is true?

	Planets move in circularorbits, with the Sun in the center of the orbit.
	Planets move in circularorbits, with the Sun located off-center.
	Planets move in ellipticalorbits, with the Sun in the center.
	Planets move in ellipticalorbits, with the Sun located off-center.

PLEASE HELP ME PICK THE RIGHT ANSWER FOR EACH QUESTIONS. PLEASEWRITE OUT THE WHOLE ANSWER AND THE LETTER. THANK YOU!

1) An object is moving with constant velocity. Which of the following statements is true?
a) A constant force is being applied in the direction of motion.
b) A constant force is being applied in the direction opposite of motion.
c) There are no forces acting on the object.
d) The net force on the object is zero.
e) There is no frictional force acting on the object.

2) You apply the same force to two objects. Object 1 has mass M and object 2 has mass 5M. The acceleration is
a) ten times that of object 1 b) five times that of object 1
c) the same as that of object 1 d) 1/5 as that of object 1

3) An object of weight W is in free-fall close to the surface of Earth. What is the force that the object exerts on Earth?
a) a force greater than W b) a force less than W
c) a force equal to W d) no force at all

4) A parking crate slides down an inclined ramp at constant velocity. Thus we can deduce that _
a) a frictional force is acting on it
b) a net downward force is acting on it
c) a net upward force is acting on it
d) it is not acted on by appreciable normal force
e) it is not acted on by appreciable gravitational force

5) A person applies a constant force of 20N to a rock of mass 1000kg for a total of 20 seconds. What is the work done by this person if the person does not move at all by this applied force?
a) 1000J b) 2000J c) 20,000J d) 0J e) 400J

6) If the net work done on an object is positive, then the object's kinetic energy.
a) decreases b) remains the same c) increases d) is zero

7) You throw a ball straight up. Compare the sign of the work done by gravity while the ball goes up with the sign of the work done by gravity while it goes down.
a) Work is + on the way up and + on the way down
b) Work is + on the way up and - on the way down
c) Work is - on the way up and + on the way down
d) Work is - on the way up and - on the way down

lavenderbat941

1) An object is moving with constant velocity. Which of thefollowing statements is true?
a) A constant force is being applied in the direction ofmotion.
b) A constant force is being applied in the direction opposite ofmotion.
c) There are no forces acting on the object.
d) The net force on the object is zero.
e) There is no frictional force acting on the object.

2) You apply the same force to two objects. Object 1 has mass M andobject 2 has mass 5M.
a) ten times that of object 1 b) five times that of object 1
c) the same as that of object 1 d) 1/5 as that of object 1

3) An object of weight W is in free-fall close to the surface ofEarth. What is the force that the object exerts on Earth?
a) a force greater than W b) a force less than W
c) a force equal to W d) no force at all

4) A parking crate slides down an inclined ramp at constantvelocity. Thus we can deduce that _
a) a frictional force is acting on it
b) a net downward force is acting on it
c) a net upward force is acting on it
d) it is not acted on by appreciable normal force
e) it is not acted on by appreciable gravitational force

5) A person applies a constant force of 20N to a rock of mass1000kg for a total of 20 seconds. What is the work done by thisperson if the person does not move at all by this appliedforce?
a) 1000J b) 2000J c) 20,000J d) 0J e) 400J

6) If the net work done on an object is positive, then theobject's kinetic energy.
a) decreases b) remains the same c) increases d) is zero

7) You throw a ball straight up. Compare the sign of the workdone by gravity while the ball goes up with the sign of the workdone by gravity while it goes down.
a) Work is + on the way up and + on the way down
b) Work is + on the way up and - on the way down
c) Work is - on the way up and + on the way down
d) Work is - on the way up and - on the way down

ASTRO 001 Lecture 1: ASTRO001 - Lecture 1 - Gravity and the Seasons Update

Document Summary

Get access

Related Documents

ASTRO 001 Study Guide - Midterm Guide: Full Moon, Lunar Eclipse, Ecliptic

ASTRO 001 Lecture Notes - Lecture 5: Tidal Locking, Continental Drift, Red Color

ASTRO 001 Study Guide - Midterm Guide: Type Ii Supernova, White Dwarf, Reaction Rate

Related Questions