Anonymous
Anonymous asked in Science & MathematicsPhysics · 5 years ago

I don't know how to write expressions for these questions. Someone please help?

An object of mass m is initially moving forward when a net force F acts on the object in the forward direction. While the force is applied, the object travels a distance x in a time t. Write expressions for the following:

(b) The amount that the object's kinetic energy increases

(c) The amount that the object's momentum increases

(d) The amount that the object's speed increases

Update:

Anonymous is wrong. Nice try though

Update 2:

I put in Anonymous's answer and it was wrong.

Update 3:

I hate Physics and I don't understand it. Why they make us take this class I don't know.

2 Answers

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  • Anonymous
    5 years ago
    Favorite Answer

    Use Newton's second law F=ma

    and

    v^2 = u^2 + 2as

    v^2=u^2 + 2Fs/m

    v^2-u^2=2Fs/m

    1/2m(v^2-u^2) = Fs

    1/2mv^2-1/2mu^2 = Fs LHS is change in KE for ans(b)

    The RHS : Fs =force x distane or work done

    So, the work done is the change in kinetic energy from the work energy theorem.

    Use: v = u+at

    v = u +Ft/m

    v-u =Ft/m

    m(v-u) =Ft

    mv-mu =Ft LHS = change in momentum for ans c)

    Again,

    Use: v = u+at

    v = u +Ft/m

    v-u =Ft/m LHS change in velocity and ans d)

    Wrong! please explain yourself anon questioner!

  • 5 years ago

    Correct answer by anon given the question. I don't think that the questioner who prefers to remain anon has any idea about physics at all and one wonders what new breed of questioner Yahoo is encouraging who fails to accept the correct answer when given. I give anon answer a thumbs up. I bet the questioner could not even answer this simple question

    https://answers.yahoo.com/question/index?qid=20141...

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