PH-UY 1013 Lecture Notes - Lecture 3: Mt Vector, Headon, Net Force

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limehamster162

7 Sep 2016

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Applied force (fapp)- an applied force is a force that is applied to an object by a person or another object. If a person is pushing a desk across the room, then there is applied force acting upon the object. The applied force is the force exerted on the desk by the person. Gravity force(also known as weight)( fgrav)- the force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity that is directed downward towards the center of the earth. The force of gravity on earth is always equal to the weight of the object as found by the equation: Fgrav = m * g where g = 9. 8 n/kg (on earth) and m = mass (in kg) (caution: do not confuse weight with mass. )

Related Questions

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

(a) What is the weight of a 5.78 kg backpack at the surface ofthe Earth?
56.7 N ( I understand this problem after some time :) )
(b) What is the weight of the same backpack at the surface of theMoon where the acceleration due to gravity is only 1.6 m/s2?
9.37 N (as well as this problem)

(c) If the backpack is atthe surface of the Earth, and if a net force of 8 N is applied tothe backpack, what is the amount of acceleration of thebackpack?
(Not sure here)

m/s^2
I was thinking A = Fnet/m
Fnet being the total force on the object being equal to G(mass ofthe earth)/(radius of the earth)^2
(I know it isn't as simple as adding 8N to the weight of backpackat the surface of the earth, if I divide by the net force thatisn't adding the net force to the weight...Please Help)

(d) If the backpack is atthe surface of the Moon, and if the same net force is applied tothe backpack, what is the amount of acceleration of thebackpack?
(If I don't understand C of course I am confused on this problem aswell, thank you for your help in advance I can figure out where togo with this problem if I understand C)

m/s2
Please explain to me so that I understand for test

PH-UY 1013 Lecture Notes - Lecture 3: Mt Vector, Headon, Net Force

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Physics: Principles with Applications

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