Physics

Question 1

define displacement, velocity, speed, and acceleration and what units are they measured?

Answer 1

displacement is units of meters which measures the net distance from start to finish

velocity v is m/s and is the rate of change in position
delta d/delta t( change in velocity over change in time)

speed is the magnitude of velocity and is not a vector

acceleration a is the rate of change of velocity of delta v/delta t (change in velocity over change in time)

Question 2

what are the 5 big kinetic equations and what conditions can they be applied?

Answer 2

BF1: delD= 1/2(Vo+V)t   - a is missing
BF2: delD= Vot+ 1/2a(t^2)  - V is missing
BF3: V=Vo+at
BF4: delD= Vt- 1/2a(t^2)
BF5: (V^2)= (Vo^2) + 2a delD

the five ens can only be applied when the acceleration is constant– uniform

Question 3

Give the magnitude and direction of free-fall acceleration near the surface of the earth?

Answer 3

G= 9.8 m/s^2 in which the direction of g is downward which is toward the surface of the earth

Question 4

What is interia? How is it measured and state netwon’s law of interita.

Answer 4

Inierita is an object natural resistance to change when it is moving. it is measrued with mass in kg

Netwon’s law of inertia is an object will not move unless there is a gorce applied to and an object will contirue to move in the same directio nand velocty unless there is a different force acting upon in

Question 5

State Newtons second law of mation. Define net force and they units.

Answer 5

F=ma and net force is the sum of all force that are acting on an object
it is expressed in terms of newtons
1N=1kg*m/s^2

Question 6

State newtons thrid law of motion

Answer 6

every action has an equal and opposite reaction.

If an object exerts a force on object two, obkect 2 exerts an equal but opposite force back onto object one

Question 7

define weight and give two reasons why mass is different than wieght

Answer 7

Weight is the gravitaional foce acting on an object. It varies on location and is measured in newtons.
mass is not a force and is the same in every locations. It is measured on kg

Question 8

state newton’s law of gravitation

Answer 8

every pair of object exert a gravitational attraction on each other with the strength of
F= GMm/r^2

Question 9

Define normal force

Is the magnitude of the normal force on an object always equal to the object weight?

Answer 9

normal focre is the compoenet of contact force that is exerted by a surface that is perpendicular to the surface. the normal force is always equal to the object wieght

Question 10

Define friction and give the equation for the froce of kinetic friction. is there an equation for the force of static friction?

Answer 10

friction is the compoenent of the contact force that is exerted by a surface that is parallel to the surface – Fk= ukFn

there is only an equation for the maximum force of static friction before it is pushed into kinetic energy– Fsmax= usFn

Question 11

define the center of mass and how is the point located?

Answer 11

the center of mass is the point where all the object mass can be considered to be concentrated and this is where the object acts as a single particle and this is where the balance point is

for objects of masses m1m2 at the coordiantes x1, x2 to make Xcm= (m1x1 + m2x2 + …)/ (m1 + m2 + …)

Question 12

define unifrom circular motion, centripetal acceleartion adn centripetal force. Give the formulas for the magnitude of centripetal acceleration and froce. What are the directions?

Answer 12

uniform circular motiono si the constant speed motion in a circle

centripetal acceleration is the acceleration toward center of the circle that is necessary to keep object on circular path without changing its speed Ac= v^2/r
the direction is toward the center of the circle

centripetal force is the net force necessary to cause the centripetal acceleration
Fc=mac=mv^2/r
direction is toward the center of the circle

Question 13

defien the torque and lever arm, give the two equation for calculating torque?

Answer 13

torque is associated with the force F that measures F effectiveness at producing rotational acceleration

lever arm L is the distance from the pivot point to the live of the force so that the lever arm is perpendicular to F

Torque t=rFsin(theta) or t=LF

Question 14

define equilibrium

Answer 14

an object at equilibrium is Fnet=0 and tnet=0

Question 15

Define momentum, is it a vector or a scalar? Define impulse and is it a vector or scalar?

Answer 15

linear momentum = mass * velocity; p=mv

impulse is force* time: J=FdeltaT

P and J are both vectors