Show:
Newton's Laws
Two-Dimensional Motion
Uniform Circular Motion
Newton's Universal Law of Gravitation/Inclined Plane
Friction/Normal Force
100
What is Newton's first law of motion?
An object at rest, stays at rest unless acted upon by an unbalanced force.
100
What two components make up the motion of a two dimensional plane? And what two formulas are used to find the components of velocity?
The horizontal and vertical components. Vix=vicosƟ Viy=visinƟ
100
When is an object experiencing uniform circular motion?
When the applied force has a constant magnitude and always acts perpendicular to the direction of the object's velocity, the object moves in a circular path at a constant speed.
100
(a) What does Newton's Universal Law of Gravitation state? (b) What is the formula? (c) What is the gravitational force?
(a) Any two bodies attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. (b) Formula: Fg=Gm1m2/r^2 (c) The attractive force that one object exerts on another object due to their masses.
100
What is the cause of the normal force?
By the bonds that exist between molecules of a solid object. The Normal Force always acts perpendicular to the surface.
200
What is Newton's Second Law of Motion? And what is the equation associated with it?
The acceleration of an object is directly proportional to the Net force on the object and inversely proportional to its mass or inertia. Formula: Fnet=ma
200
The component parallel to the horizon is the... The component perpendicular to the horizon is the...
Parallel- Horizontal Component Perpendicular- Vertical Component
200
What is centripetal acceleration? What is the formula to find centripetal acceleration?
An acceleration directed toward the center of the circle. A vector quantity whose magnitude is directly proportional to the square of the speed of the object and inversely proportional to the radius of the circular path in which it travels. ac=v^2/r
200
At what region in space would a test particle experience a gravitational force?
In a gravitational field. Every mass unit is surrounded by a gravitational field.
200
What is static friction?
Force preventing surfaces from moving relative to each other. Matches the applied force when the net force is zero, up to a maximum amount of force.
300
What is Newton's Third Law of Motion?
For every action force there is an equal and opposite reaction Force.
300
When a projectile is fired horizontally, neglecting air resistance, the initial vertical velocity is always...
Zero
300
What is centripetal force? What is the symbol?
The force needed to keep an object moving in a circular path. The symbol is Fc.
300
Calculate the magnitude of the gravitational force of attraction that Earth exerts on the Moon.
Fg= 1.99x10^20N
300
What is kinetic friction?
Force resisting motion when surfaces are sliding relative to each other. The amount of kinetic friction is less than maximum amount of static friction. Amount of kinetic friction remains constant- does not depend on applied force.
400
(a) What are the differences between mass and weight? (b) What is the relationship between mass and weight?
(a) Mass-- Amount of matter contained within an object, Mass doesn’t change with a change in location Weight- - The force of attraction between two objects with mass, Weight generally changes with a change in location (changing to a place other than earth) (b) Direct Relationship--> Fg=mg
400
When air resistance is neglected, is there a change in acceleration or a change in velocity in the horizontal direction?
There is no change in either acceleration nor velocity in the horizontal direction when air resistance is neglected.
400
What is the formula for Centripetal Force? Which of Newton's Laws is the formula for Centripetal Force derived from?
Fc=ma_c Centripetal Force's formula is derived from Newton's Second Law of Motion, F=ma.
400
Calculate the force of tension in the rope holding a 5.0kg box held at rest on a hill whose angle of inclination is Ɵ=30º.
FN=43.3N
400
(a) What are the factors that influence friction? (b) What are the factors that do not influence friction?
(a) Normal Force, and Relative Roughness of the surfaces that touch (b) Surface Area, and speed or applied force (once the object is sliding)
500
If the sum of all the forces acting on a moving object is zero, the object will...
Continue moving with constant velocity.
500
A plane flying horizontally at an altitude of 490 meters and having a velocity of 250 meters per second east, drops a supply packet to a work crew on the ground. It falls freely without a parachute. (Assume no wind and negligible air resistance.) (a) Calculate the time required for the packet to hit the ground. (b) Calculate the horizontal distance from the target area that the plane must drop the packet.
(a) t= 10s (b) d= 2500 meters west
500
Why does an object in uniform circular motion travel at a constant speed in its circular path, and why is it not in equilibrium?
An object in uniform circular motion travels at a constant speed in its circular path because there is no net force acting on the object in its direction of motion. The object is not in equilibrium centripetal force acts perpendicular to the tangential velocity and produces constant acceleration towards the center of curvature.
500
Calculate the force of friction acting on this box if it accelerates down the incline at a rate of .67m/s^2.
Ff=12.4N
500
In lab, the coefficient of kinetic friction for dragging a brick across a tabletop is found from experiment to be .23. How much force would you need to drag a 2.0kg brick across a tabletop at constant speed?
4.6N