Math Algebra 1

Your cell phone plan costs ​$24.99per month plus ​$0.18 for each text message you send or receive. You have at most ​$33to spend on your cell phone bill. What is the maximum number of text messages... more


Math Variations

The gravitational force, , between an object and the Earth is inversely proportional to the square of the distance from the object to the center of the Earth. If an astronaut weighs 199 pounds on... more


magnitude and direction

Two forces F1 and F2 are applied to an object whose mass is 11.1 kg. The magnitude of F1 is larger than that of F2. When two forces point due east, the object has an acceleration whose magnitude is... more


magnitude and direction

Three coplanar forces acts on a block with mass m =70.0 kg. One is 23.2 N directed at 14.10, another is 35.4 N directed at 1390, the other is 77.7 N directed at 2890. What are the magnitude and... more


statistics assistance needed

Assume you put $600 per month into a retirement account for 13 years, and the account has an APR of 3.04% compounded monthly. What is the account balance at the end of the 13 years? Round your... more


patrotism and nationalism

So, my first question is: But can a dissident (someone who expresses their disagreement with their own country) be considered patriotic? So, second question: is this a valid argument... more


Is Newton's third law always correct?

Newton's third law states that every force has an equal and opposite reaction. But this doesn't seem like the case in the following scenario: For example, a person punches a wall and the wall... more


Are Newton's "laws" of motion laws or definitions of force and mass?

If you consider [them](http://en.wikipedia.org/wiki/Newton%27s_laws_of_motion) as laws, then there must be independent definitions of [force](http://en.wikipedia.org/wiki/Force) and... more


If action equals reaction, how is it ever possible to win in martial arts?

In kick-boxing, when a fighter's leg hits an opponents leg, the outcome, based on Newton's 3rd law, should be the same for each fighter. It's not even important who kicked who, as in the moment of... more


Why do whips hurt so much?

What exactly is the mechanism that makes a whip deliver such a strong impact? Elasticity, torque, or pressure? Just hitting something with a plank doesn't deal nearly as much damage. What's the... more

Physics elevator question

An elevator has an upward acceleration of 3.2 m/s^2. How much does an occupant of mass 80 kg weigh in Newtons while riding in the elevator?

What is modal logic for?

I understand "pure" logic as a structural description of what a valid proof is but I have never understood the reasons for using modal logic. What's an example typical of how modal logic is used?

What is the difference between a statement and a proposition?

I'm doing a MOOC on mathematical philosophy and the lecturer drew a distinction between a proposition and a statement. This is very puzzling to me. My background is in math and I regard those two... more

What is the difference (if any) between "not true" and "false"?

A fairly simple question I hope someone can help me with.

Is circular reasoning always a fallacy?

Suppose the following dialogue: >... >"I accept only one notion of land property. Namely, 'I am doing my stuff here, therefore I am here". >"But this means," he responded, "you can break... more


Why do some people care so much about "empirical truth"?

Whenever you discuss philosophy, inevitably you will come across a type of person who holds empirical truth above all else, and will blatantly ridicule any discussion which has its onset in a... more

How can we reason about "if P then Q" or "P only if Q" statements in propositional logic?

When you have a propositional sentence of the form ***P* ⊃ *Q*** — which we might read as "if *P*, then *Q*" — how can you tell when it is true, or false, based on the truth-values of *P* and *Q*... more

Can an argument be valid even though one of its premises is false?

Is it possible for an argument to be valid by virtue of its logical form, but contain a false premise? In other words, can a premise be false even though the argument itself is logically valid?

Could 'cogito ergo sum' possibly be false?

I've heard it postulated by some people that *"we can't truly know anything"*. While that does seem to apply to the vast majority of things, I can't see how *'cogito ergo sum'* can possibly be... more

What does Hobbes believe is the true definition or state of leviathan?

Is this a logical state 


A sound argument is a valid argument with no false premises

Logic phil 60


How do I show that [p ? (q ? r)] = [p ^(¬r) ? (¬q)]

[p ⇒ (q ⇒ r)] = [p ^(¬r) ⇒ (¬q)]

Using Logical simplification

Could someone help me on the question below please.   Using Logical simplification, prove that the following are tautologies, contradictions or neither. Verify your answers using a truth... more

1) ?P(c = b?P(c)) 2) ?x( f (b) = x)) (note: ? means backwards E)

Suppose we have an FOL with names/constants a,b,c,d, variables x,y, z, function symbolsf (x),g(x),h(x,y), predicate symbols P(x),Q(x),R(x,y),x = y, the usual connectives and the quantifiers∀,∃. For... more
1 3

Still looking for help? Get the right answer, fast.

Ask a question for free

Get a free answer to a quick problem.
Most questions answered within 4 hours.


Find an Online Tutor Now

Choose an expert and meet online. No packages or subscriptions, pay only for the time you need.