The hammer throw is a track and field event in which a 7.01-kg ball (the \"hamme
ID: 2188247 • Letter: T
Question
The hammer throw is a track and field event in which a 7.01-kg ball (the "hammer"), starting from rest, is whirled around in a circle several times and released. It then moves upward on the familiar curving path of projectile motion. In one throw, the hammer is given a speed of 29.0 m/s. For comparison, a .22 caliber bullet has a mass of about 2.68 g and, starting from rest, exits the barrel of a gun with a speed of 393 m/s. Determine the work done to launch the motion of (a) the hammer and (b) the bullet.Explanation / Answer
SIMILAR ONE PLEASE RATE The hammer throw is a track and field event in which a 7.3 kg ball (the "hammer"), starting from rest, is whirled around in a circle several times and released. It then moves upward on the familiar curving path of projectile motion. In one throw, the hammer is given a speed of 29 m/s. For comparison, a .22 caliber bullet has a mass of 2.6 g and, starting from rest, exits the barrel of a gun with a speed of 410 m/s. Determine the work done to launch the motion of (a) the hammer and (b) the bullet. ANS: To solve this problem, we must assume that energy is conserved. (This isn't stated in the problem, and is not true in general in these real-world examples, however we must assume conservation of energy in order to solve the problem with the information given). Work = Kinetic Energy = (0.5)(mv^2) For Work in Joules, the mass is in units of Kg, and the velocity is in units of m/s. ------------- (a) KE(hammer) = 1/2mv^2 = 1/2 x 7.3 x (29)^2 = 3.1 x 10^3 J (b) KE(bullet) = 1/2mv^2 = 1/2 x 2.6 x 10^-3 x (410)^2 = 2.2 x 10^2 J
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