(adsbygoogle = window.adsbygoogle || []).push({}); 1.)

x(t) = a + b*t

y(t) = c + d*t + e*t*t

a= 70 cm, b=38 cm/s, c=78 cm, d=17 cm/s and e=-490 cm/s/s

What is the initial velocity of this projectile?

I approached it assuming that the angle is 45 degrees. So I used the pythagorean therom to solve for the hypotnuse given that we already have the vertical and horizontal velocities. Is this correct or am I missing something here?

2.) A 510 gram ball is moving through the air. At this moment, the horizontal component of its velocity is vx=9.43 m/s and the vertical component of its velocity is vy=4.70 m/s.

What is its kinetic energy now?

I did an online quiz and used the pythagorean theorem again. Somehow I got the right answer on another exact problem with different numbers. Is the pythagorean only involved in this problem?

3.) A bullet is being shot straight up with a mass of 35.58gm and a velocity of v=176m/s. What is its kinetic energy in 47.91 seconds?

For this one, I assumed a force of -9.8m/s/s was present on the bullet being shot straight up. I multiplied 47.91 to -9.8, and added that value to 176. The outcome of this should be the instant where we need to find the KE. I than used the KE=.5M+(V*V) formula to find the answer. Am this the correct method to solving it? The online quiz keeps telling me I've been getting the wrong answer.

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# Homework Help: Calculating problems with x and y components and other questions

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