A projectile is shot upward from the surface of Earth with initial velocity of 116 meters per second. Use the position function below. What is its velocity after 2 seconds? After 10 seconds?

Question

s(t) = −4.9t² + v₀t + s₀

2s:____m/s

10s:___m/s

Answer 1

 Hi Celine. You could use Calculus and differentiate the formula for position with respect to time to obtain the formula for velocity at any given time. However in this case, assuming zero air resistance, you could use the fact that upward velocity is decreasing linearly at a rate of minus 9.8 meters per second per second which is the acceleration due to gravity. Thus for example after 2 seconds, the velocity is now +116 - 9.8*2 meters per second, or +96.4 m/s. Do the same thing for t = 10 seconds.

Robert