Posted by **Vanessa** on Thursday, July 10, 2008 at 1:50pm.

A science project studying catapults sent a projectile into the air with an initial velocity of 30 m/s. The formula for distance (s) in meters with respect to time in seconds is

s = -4.9t2 + 30t. Find the instantaneous rate of change (and thus the velocity at any time) using and then find the instantaneous rate of change at:

t = 1

t = 3

- URGENT, Calculus! -
**drwls**, Thursday, July 10, 2008 at 3:47pm
That formula applies only if the projectile is launched straight up. That would not be a practical way of launching an object with a catapult, unless you are doing a Monty Python movie and launching dead cows.

Unless the motion is in a straight line, as it is in this case, the rate of change of the distance away, ds/dt, is NOT the velocity.

Having said that, the rate of change of s is 30 - 9.8t m/s

Plug in t = 1 and then t=3 for the velocities they ask for.

## Answer This Question

## Related Questions

- Maths - When a ball is thrown up into the air, it makes the shape of a parabola...
- math - When a ball is thrown up into the air, it makes the shape of a parabola. ...
- physics - What is the velocity of a projectile with initial velocity 2m/s at an...
- Physics - A projectile is fired with an initial velocity of v0 feet per second...
- Math - A projectile is fired with an initial velocity of v0 feet per second. The...
- Algebra - When a ball is thrown up into the air, it makes the shape of a ...
- math - The height in meters of a projectile launched from the top of a building ...
- algebra - Use the formula 4.9t^2 +vot=s, where t is the time in seconds, vo is ...
- College algebra - When a ball is thrown up into the air, it makes the shape of a...
- math - The height of a projectile fired upward is given by the formula s = v0t...

More Related Questions