Use complete sentences and clearly indicate which part of the question you are a
ID: 110216 • Letter: U
Question
Use complete sentences and clearly indicate which part of the question you are answering. A baseball game in space. Taking a break from assembling the space station, a bunch of astronauts decide to try playing baseball. They put on their spacesuits and jetpacks and go "outside" to play. In each part, when I say "what happens to" I mean does he or it start or stop moving? How fast and in what direction? In each case explain how you know the answer to the question (a) After each of the players has found a good spot and used his jetpack to stop moving relative to the space station, the pitcher revs up and throws what on Earth would be a good curve ball. What happens to the ball in space? What happens to the pitcher? Assume the ball has a mass of 0.1 kg, the pitcher has a mass (in his suit) of about 100 kg, and he pitches with a speed of 10mls (b) The batter takes a crack at the ball and connects, the ball heads back the way it came at about twice the speed it had when it arrived. What happens to the batter? (c) The ball heads straight out into left field, where another astronaut catches it What happens to him? (d) Would any of these answers be different if they were playing inside the space ship and without their space suits? Explain.Explanation / Answer
Newtonian Mechanics is applied to exolain the answers.
(a) The ball continues to move in a straight line in space. The reason behind this is that the outer space is considered to be a vacuum as it has very low density and very low pressure such that the density and pressure can be considered to be negligible. Absence of any aerodyanamic forces in outer space causes the ball not to return back to the pitcher. If a small pressure is present anywhere, then the curve ball would exhibit a slightly curved path. Otherwise it would continue to move in a staight line unless it encounters some gravity (as the Earth's gravity).
The pitcher throws the ball and according to Newton's third law of motion (Every actipon has an equal and opposite reaction), the pitcher moves in a direction opposite to that of the direction of movement of the curve ball. The force applied to the curve ball (F) is equal to the product of the mass of the curve ball (m) and the acceleration of the curve ball (a). So, an identical reaction force is applied upon the pitcher (F').
Thus, F= m*a= F'
Mass of the curve ball is 0.1 Kg while mass of the pitcher is 100 Kg. Thus, the pitcher is 1000 times more heavier than the curve ball (100/ 0.1). The 100 Kg pitcher accelerates the 0.1 Kg ball with a speed of 10m/s. The pitcher's body experiences an opposite reaction at a speed which is 1/1000 times more than the curve ball i.e. at 10/1000 = 1/100 m/s or 0.01 m/s.
(b) When the batter throws the ball at twice the speed at which the ball had arrived, the batter would have moved back in the opposite direction with the same speed i.e. at the same speed at which he had thrown the ball / twice the speed at which the ball had arrived. This happens according to Newton's Third Law of Motion: EVery action has an equal and opposite reaction.
(c) Principle of conservation of momentum and Newton's third law of motion can be applied to explain this answer. The two astronauts move away from each other (Newton's third law) a little faster (Principle of conservation of momentum). When the first astronaut throws the ball, he moves backwards and when the second astonaut catches the ball, he moves backwards. Meanwhile, the net momentum is conserved.
(d) Yes, the above answers would be different if they were playing inside the space shuttle as there would be objects inside the space shuttle that would have hindered the progress of the curve ball. The curve ball would have returned to the pitcher as it is comparatively airy inside the space shuttle. Uneven forces act on different parts of the curved body of the curve ball and thus, the ball would move in a circular path towards the pitcher. This is analogous to the movement of a wheel on Earth. Thus, drag forces inside the space shuttle cause the curve ball to move slower as compared to its movement outside the space shuttle.
The space suit renders a certain weight to the pitcher/any other player and thus, it would affect the action and reaction forces to change their magnitude (as we have seen that F=m*a).
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