1. free fall

The equation for free fall at the surface of a planet is $s=3.8t^2m$ with $t$ in seconds. Assume a rock is dropped from the top of a 400-m cliff. Find the speed of the rock at $t$=6 sec.

I came up with the answer 45.6 m/sec using the slope of the curve formula, but do not fully understand what I did, or if it is correct. Can anyone explain how to correctly solve?

Thanks!

2. Originally Posted by live_laugh_luv27
The equation for free fall at the surface of a planet is $s=3.8t^2m$ with $t$ in seconds. Assume a rock is dropped from the top of a 400-m cliff. Find the speed of the rock at $t$=6 sec.

I came up with the answer 45.6 m/sec using the slope of the curve formula, but do not fully understand what I did, or if it is correct. Can anyone explain how to correctly solve?

Thanks!
speed,v= $\frac{ds}{dt}$ $=7.6t$

Slope of a curve means the slope of the tangent to curve.