How fast must a 2.5-g ping-pong ball move in order to have the same kinetic ener

Question

How fast must a 2.5-g ping-pong ball move in order to have the same kinetic energy as a 145-g baseball moving at 30.0 m/s? An athlete with a mass of 60.0 kg is in a cross country race, and at one instant he has a speed of 4.20 m/s. (a) What is his kinetic energy at this instant? KE_i = J (b) If he wishes to doubles his speed to reach the finish line, his kinetic energy will change by what factor? Jet fighter planes are launched from aircraft carriers with the aid of their own engines and a catapult. If in the process of being launched from rest, the thrust of a jet's engines is 2.70 times 10^5 N and after moving through a distance of 90 m the plane lifts off with a kinetic energy of 4.70 times 10^7 J, what is the work done on the jet by the catapult? J

Explanation / Answer

KE of the base ball is:

KE(bb) = 1/2 m v^2 = 0.5 x 145 x 10^-3 x 30^2 = 65.25 J

Now we have consition given, KE(pp) = KE(bb)

1/2 m vp^2 = 65.25

vp^2 = 65.25 x 2/2.5 x 10^-3 = 52200

vp = sqrt(52200) = 228.47 m/s

Hence, vp = 228.47 m/s

Related Questions

Navigate

• Browse (All)
• Browse H
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.