gifty91 Group Title Superman dangles his watch from a thin piece of string while he is taking off from the ground horizontally at a constant acceleration a. He notices that the string makes an angle (theta) with respect to the vertical. After 20 seconds, his speed is v=134 m/s. Estimate the angle (theta). 2 years ago 2 years ago

1. CreAtivSpelErr

Use the time and final velocity to find the horizontal acceleration. Use Newton's 2nd Law and do a vector triangle with forces. The vertical force is mg, the horizontal force is ma (the force superman needs to exert on the watch to give it a horizontal acceleration of 'a'). $\tan \theta = \frac{ mg }{ ma }$ and the unknown mass of the watch cancels.