Why does Time pass more slowly for observers traveling at high speeds or near a massive body.

PASS Content Standard 2.1

Objects change their motion only whena net force is applied. Laws of motion areused to determine the effects of forceson the motion of objects.

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Motion - 12 min

• Earth rotates on its axis at 1,100 mph

• Earth orbits the Sun at 68,000 mph

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• The whole galaxy rotates at 490,000 mph

Two Dimensional World

Speed - 4 min

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Speed =distance

time

Speed =distance

time

A snail crawls 10 feet in 5 minutes.What is the speed of the snail?

=10 feet

5 minutes= 2 feet/min

Average speed =total distance

total time

Average speed =total distance

total time

A boy runs 1 mile in 6 minutes, rests for2 minutes, then walks 1 mile in 12minutes. What is his average speed?

=1 mile + 1 mile

20 minutes=

2 miles

20 minutes

Distance(meters)

Time (seconds)

is a vector quantitybecause it has bothspeed and direction.

Vectors - 12 min

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All these planes have the same speed.

How istheirvelocitydifferent?

The length of the line representsthe quantity (speed) and the arrowindicates the direction.

Add vectors head to tail.

Direction isindicated bycompass degrees

The magnitude of the speed isindicated bythe measuredlength (scale) of the line.

0o

90o

180o

270o

An airplane is flying 200mph at 50o. Wind velocityis 50 mph at 270o. Whatis the velocity of the plane?

0o

90o

180o

270o

Acceleration =Velocity(final) - Velocity(original)

time


time

A car traveling at 60 mph accelerates to90 mph in 3 seconds. What is thecar’s acceleration?

=90 mph - 60 mph

3 seconds

=30 mph

3 seconds

= 10 mph/second


time

A car traveling at 60 mph slams on the breaks to avoid hitting a deer. The car comes to a safe stop 6 seconds after applying the breaks. What is thecar’s acceleration?

=0 mph - 60 mph

6 seconds

=- 60 mph

6 seconds

= - 10 miles per hour per second

Acceleration toward thecenter of a circular path.

For an object to travel in acurved path, some force mustbe accelerating it toward the center of the circle.

Force providedby engine

Accelerationprovided by tires

What happens if the acceleratingforce is removed?

An apparent forcethat appears only in rotating frames of reference.

This “false” forceappears to pushaway from thecenter of thecircular path.

Aristotle and Newton had differentideas about forces and motion.

Aristotle's idea: For anobject to move at a constantspeed, a constant forcemust be applied.

Newton's idea: An objectmoving at a constant speedwill continue at that speedwithout additional forcebeing applied.

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Forces & motion - 6 min


ProduceNO

Motion

Produce Motion

Sliding - two solid surfaces rubbing against each other.

Rolling - an object rolling over a surface.

Fluid - an object moving through a fluid.

Newton’s Laws - 5 min


An object at rest willremain at rest, and amoving object willremain at a constantvelocity unless actedon by unbalanced forces.

Force = mass X acceleration

F = Ma

For every action,there is an equaland oppositereaction.

Rockets - 6 min


Momentum - 8 min


Does a long pendulum swingfaster than a short one?

Does a heavy pendulum swingfaster than a light one?

The total momentum ofany group of objectsremains the same unless acted on byoutside forces.

Elastic - occur when both momentumand kinetic energy are conserved.

Inelastic - occur when momentum is conserved, but kinetic energy is not.

M1V1 = M2V2

Before After



Colliding objects have same mass

Elastic Collision

Heavy object strikes light object



Elastic Collision

Light object strikes heavy object



Elastic Collision

Inelastic Collision



Colliding objects have same mass

Rollercoasters - 24 min


Units of Force are Newtons

Units of Distance are Meters

Newton Meters = Joules

Units of Work are Joules

Joules per second = Watts

Power is the rate at which work is done.

Work & Power - 15 min


power - 2 min


1 Horsepoweris equal to

745.56 Wattsor

550 ft lb/sec

Climbing cars - 24 min


The effort force isapplied to a machine.

The resistance force isapplied by a machine.

The number of times a machinemultiplies the effort force.

Work output Work input X 100

Da Vinci - 8 min


Work is made easier because the effort force moves over a greater distance.

Inclined Plane - 2 min


Force is multiplied since it is applied to a wide area and exerted over a small area.

Wedge - 2 min


Multiplies an effort force by acting through a long effort distance.

Screw - 1 min


A bar which can movefreely around a fixed position, or fulcrum.

Levers - 3 min


The Fulcrum is betweenthe Effort Force and the Resistance force

Multiplies Effort Force and changes its direction

The Resistance is between the Effort Force and the Fulcrum

Multiplies the Effort Force butdoes not change its direction

The Effort force is between the Resistance Force and the Fulcrum

Does not multiply the Effort Force

Direction of the Effort Force is changed.

Mechanical Advantage = 0

Direction of the Effort Force is not changed.

Mechanical Advantage = 1

Direction of the Effort Force is changed.

Mechanical Advantage is equal to the number of supporting ropes.

Pulleys - 1 min


A fixed pulleydoes not havea mechanicaladvantage.

Fixed pulleysonly changethe directionof the force.

A movable pulleydoes have amechanicaladvantage.

The effort forceis in the directionof the movementof the resistance.

Two wheels of different sizes connected - the axle being the smaller wheel.

Wheel & Axle - 1 min


Worm Gear

Compound Machines - 4 min


Why does Time pass more slowly for observers traveling at high speeds or near a massive body.

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Transcript of Why does Time pass more slowly for observers traveling at high speeds or near a massive body.