Can any one help me to solve this question? A diver starts jumping from a platform of height 10 meters above water surface, if the height of the diver above water surface $S$ metres is determined by the relation: $S=-4.9t^2+3.5t+10$, where $t$ is the time in seconds, after how many seconds the driver will reach the water surface?
Relations and Functions (Applications)
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linear-algebra
functions
relations
1 Answers
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Given $S = 10$, you have $10 = -4.8t^2+3.5t+10$. By moving 10 to the right-hand side, you'll get:
$$-4.9t^2+3.5t=0$$ $$t(-4.9t+3.5)=0$$
So the time can be either $0$ or $\frac{3.5}{4.9}$. Since we're talking about a real-life problem here, the time can't be $0$ (he can't teleport to the water), thus $t=\frac{3.5}{4.5}\simeq0.7$.