Suppose that a pitcher can throw a ball straight up at100mi/h

(about 45 m/s). Use energy conservation to calculate how high the baseball goes, Explain your work. Actually, a pitcher can’t attain this high a speed when throwing straight up, so your result will be an overestimate of what a human can do; air resistance also reduces the achievable height

Short Answer

Expert verified

The baseball goes 103.21 m in height

Step by step solution

01

Identification of Given Data

The speed of the baseball is45m/s

02

Significance of principle of energy conservation

The energy is produced or destroyed as per the conservation of energy principle. The principle says that the experimental observations depend on the cogency of the energy conservation.

According to the principle of energy conservation,

Loss of potential energy = Gain in kinetic energy

03

Calculation of the height goes by the baseball

To find the height goes by the baseball, we have to apply Principle of energy conservation,

h=v22g.........(1)

Where,

h=heightgoesbybaseballv=speedoftheball45m/sg=accelerationduetogravity9.81m/s

Substitute the values in Equation,

h=4522×9.81h=103.21m

Hence, the baseball goes103.21 mheight.

  • If we throw a baseballstraight up, it will experience deacceleration due to gravity.
  • When a baseball reaches maximum height, the kinetic energy will be zero.
  • The potential energy will become high.
  • When the gravitational force starts accelerating, the kinetic energy will become high.

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Most popular questions from this chapter

One mole of helium atoms has a mass of 4grams. If a helium atom in a balloon has a kinetic energy of1.437×10-21J, what is the speed of the helium atom? (The speed is much lower than the speed of light.)?

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A proton(H1)and a deuteron ((H2), “heavy” hydrogen) start out far apart. An experimental apparatus shoots them toward each other (with equal and opposite momenta). If they get close enough to make actual contact with each other, they can react to form a helium-3nucleus and a gamma ray (a high-energy photon, which has kinetic energy but zero rest energy):H1+2H3He+y

This is one of the thermonuclear or fusion reactions that takes place inside a star such as our Sun.

The mass of the proton is 1.0073 u(unified atomic mass unit,1.7×10-27kg), the mass of the deuteron is 2.0136 u, the mass of the helium-3nucleus is 3.0155 u, and the gamma ray is massless. Although in most problems you solve in this course it is adequate to use values of constants rounded to two or three significant figures, in this problem you must keep at least six significant figures throughout your calculation. Problems involving mass changes require many significant figures because the changes in mass are small compared to the total mass. (a) The strong interaction has a very short range and is essentially a contact interaction. For this fusion reaction to take place, the proton and deuteron have to come close enough together to touch. The approximate radius of a proton or neutron is about1×10-15m. What is the approximate initial total kinetic energy of the proton and deuteron required for the fusion reaction to proceed, in joules and electron volts (1eV=1.6×10-19J)? (b) Given the initial conditions found in part (a), what is the kinetic energy of theHe3plus the energy of the gamma ray, in joules and in electron volts? (c) The net energy released is the kinetic energy of theHe3plus the energy of the gamma ray found in part (b), minus the energy input that you calculated in part (a). What is the net energy release, in joules and in electron volts? Note that you do get back the energy investment made in part (a). (d) Kinetic energy can be used to drive motors and do other useful things. If a mole of hydrogen and a mole of deuterium underwent this fusion reaction, how much kinetic energy would be generated? (For comparison, aroundare obtained from burning a mole of gasoline.) (e) Which of the following potential energy curvesin Figure 6.87 is a reasonable representation of the interaction in this fusion reaction? Why?

As we will study later, the average kinetic energy of a gas molecule is32kbT, whereis the “Boltzmann constant,”1.4×10-23J/K, andis the absolute or Kelvin temperature, measured from absolute zero (so that the freezing point of water is273K). The approximate temperature required for the fusion reaction to proceed is very high. This high temperature, required because of the electric repulsion barrier to the reaction, is the main reason why it has been so difficult to make progress toward thermonuclear power generation. Sufficiently high temperatures are found in the interior of the Sun, where fusion reactions take place.

The point of this question is to compare rest energy and kinetic energy at low speeds. A baseball is moving at a speed of 17m/s. Its mass is 145g(0.145kg). (a) What is its rest energy? (b) Is it okay to calculate its kinetic energy using the expressionrole="math" localid="1657713286046" 12mv2? (c) What is its kinetic energy? (d) Which is true? A. the kinetic energy is approximately equal to the rest energy. B. the kinetic energy is much bigger than the rest energy. C. the kinetic energy is much smaller than the rest energy.

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