Physics Unit 2 Newton's Second Law Quiz Review

dynamic equilibrium

moving at constant velocity, 0 net force, 0 acceleration

directly

Acceleration is __________ proportional to net force

friction

dependent on the kinds of materials and how much they are pressed together. Caused by tiny surface bumps and to the "stickiniess" of the atoms on the materials surface. ex: tile floor vs carpet
Can occur with sliding objects(not dependent on speed), in water(dependent on speed), and in air(drag)
Direction of friction opposes direction of mtion

more (static force is stronger than Kinetic force)

It takes ____ force to get object going than to keep it sliding

same

acceleration is always in ______ direction as net force (and inversely proportional to mass)

mass

the quanity of matter in an object. Also the measure of the inertia or sluggishness that an object exhibits in any effort made to start it, stop it, or change its motion in any way.
Greater inertia = greater mass
kg unit of measurment

weight

the force upon an object due to gravity.
mass and weight is directly proportional
N (newton) scientific unit of force
lbs is another unit
Weight = mass x acceleration

inversely

mass and acceleration are ________ proportional
Acceleration = 1/mass

60 m/s

at one instant, an object in free fall has a speed of 40 m/s. It's speed 2 seconds later is what?

force gravity pulling it downward and air drag force acting upward.

when an object falls downward through the air (with air resistance) it experiences two things:

nonfree fall

The condition of _____________ _____ occurs when there IS air resitance and is dependent on speed and frontal surface area.

terminal speed

occurs when acceleration terminates. When air resistance = weight and net force bcomes zero.

terminal velocity

the same as terminal speed, but with direction impled

decreases, increases

as the skydiver continues to fall faster and faster through the air, her acceleration and netforce _______ while air resitance ________

nonfree fall vs. free fall

object falling while air resitance is present (FF) vs object falling in a vacuum where there is no air resitance (NFF)

Newton's Second Law

Force = mass x acceleration

Zero

When an object's acc is _____ it's netforce is zero

Triple

If u triple the net force on an object, you ____ it's acceleration

10

A box is pulled by a force of 25 N and at same time is pulled down by a force of 15 N. The resultant force on the box is ____ N

Same

Compared to the mass of an elephant on earth the mass of the elephant on the moon is the ___

Kilogram

The SI unit for mass is

The one on the moon

A rock weighs 50 N on Earth and another rock weights 50 N on the moon which rock has greater mass

10 kg

A dog that weights 100 N has a mass of

Force

The newton is a unit of

3000 kg

A tow truck exerts a force of 6000 N on a car, which then accelerates at 2 m/s squared. What is the mass of the car

12 m/s squared

An object released from rest on a planet takes 1 second to fall a distance of 6 m. What is the acceleration due gravity on this planet

True

Static friction is normally greater than sliding friction, true or false

false, they are inversely proportional

Acceleration is directly proportional to mass true or false.

500 N

Calculate the weight in N of a person who has a mass of 50 kg

0

When a falling obj has reached its terminal velocity its acceleration is

True

Speed and surface area affect the force of air resistance, true or false?

False

A lighter parachutist will fall faster than a heavier parachutist who wears a parachute of the same size, true or false?

the faster one

If two objects of the same size fall thru the air at diff speeds, which will encounter the greater air resistance?