A boy kicks a football with an initial velocity of 20 m/s at an angle of 25° above the horizontal.If we neglect air resistance,the magnitude of the acceleration of the ball while it is in flight is A)25 m/s². B)18 m/s². C)9.8 m/s². D)8.5 m/s². E)0 m/s².

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Quizplus · Accepted Answer

Since we are neglecting air resistance, the only force acting on the ball is gravity which points vertically downwards with magnitude 9.8 m/s^2. The initial velocity of the ball has a horizontal component (20*cos(25)) and a vertical component (20*sin(25)). The horizontal velocity is constant (since there is no force acting on it), while the vertical velocity changes due to the force of gravity. Therefore, the magnitude of the acceleration of the ball while it is in flight is equal to the magnitude of the gravitational acceleration, which is 9.8 m/s^2.

A Boy Kicks a Football with an Initial Velocity of 20