About the experiment of the car with a ball, rolling frictionless at constant sp
ID: 1393477 • Letter: A
Question
About the experiment of the car with a ball, rolling frictionless at constant speed on a horizontal track, at some point the ball get launched up vertically. Assume the ball density is high enough to ignore air friction. Now discuss these other two situations (i) Inclined track instead of horizontal track. The car goes down the track, no friction between car and track. (ii) Inclined track. The car goes down the track, there is some friction between car and track. (iii) Inclined track. The car goes down the track, without friction between car and track. Now assume there is some air resistance on the ball. Give a detailed explanation of why the ball will fall behind, into, or in front of the car, indicate if your argument agrees with or challenges against the assumption that motion along perpendicular directions are independent. (iv) Describe another situation you encountered where you can clearly see that motions along perpendicular directions are independent
Explanation / Answer
(I) The situation is the same as that motion is carried horizontally. Therefore, the ball will fall back into the car.
(II) In this case. the speed of the car will be diminished. But this will also affect the output speed of the ball. For this reason, it will fall back into the car.
(III) Now the ball is delayed by effect of friction with air. The forces of this nature are proportional to the object velocity. Causing a decrease in the speed of the ball, and thus a reduction in the maximum scope thereof. All this results in that the ball falls behind the car.
(IV) If you drop a box from an airplane. (this can be scaled with a toy model) It is clearly seen as the vertical speed varies. While his shadow will keep constant horizontal velocity.