## Physics for Scientists and Engineers: A Strategic Approach with Modern Physics (3rd Edition)

(a) $y = \frac{1}{2}at^2$ $y = \frac{1}{2}(9.80~m/s^2)(4.0~s)^2$ $y = 78.4~m$ The tower should be 78.4 meters high. (b) $v = v_0+at = 0 + at$ $v = (9.80~m/s^2)(4.0~s)$ $v = 39.2~m/s$ The impact velocity is 39.2 m/s