PHYS 201 Study Guide - Midterm Guide: Friction, Net Force, Inertial Frame Of Reference

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apricottermite744

9 Sep 2015

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Phys 201: problem notes for force, friction, tension, and newton"s laws. Frictional force and static and kinetic friction: the frictional force of an object at rest is 0n. If a force (push or pull) is acting on the object, but the object is not moving, the frictional force equals the pull/push force but is opposite in direction. Inclined planes: for inclined planes, make the y-axis go along the normal force, the x-axis will go along the frictional force. If fp is along the x-axis, the fgsin(theta) = fgx. If the force of tension (ft) is in the y direction and the object is at rest or constant velocity, the tension equals the fg. In hanging masses, tension is greater above both objects because of mass. In a pulley system, the ft in the right direction for the object on the table equals the ft upwards for the hanging object.

Related Questions

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

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

Learning Goal: To understand kinetic and static friction.

A block of mass M lies on a horizontal table. The coefficient ofstatic friction between the block and the table is us. Thecoefficient of kinetic friction is uk, with uk<us .
A.If the block is at rest (and the only forces acting on the blockare the force due to gravity and the normal force from the table),what is the magnitude of the force due to friction?

Part B
Suppose you want to move the block, but you want to push it withthe least force possible to get it moving. With what force F mustyou be pushing the block just before the block begins tomove?
Express the magnitude of in terms of some or all the variables f,us,uk, and m, as well as g the acceleration due to gravity .

PHYS 201 Study Guide - Midterm Guide: Friction, Net Force, Inertial Frame Of Reference

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