You are rollerblading at a constant 4.5m/s, you reach a down hill and start to accelerate at 2.65 m/s for the next 70meters. What is your final velocity? How long does it take to go the 70 meters.?
thanks in advance, and explain how u got it!
2007-09-23 09:12:48 · 1 answers · asked by Anonymous in Science & Mathematics ➔ Physics
A common but very useful formula to use is:
(Vf)^2 = (Vi)^2 + 2*a*D
with Vf the final velocity and Vi the initial velocity. Here you have Vi = 4.5m/s, a = 2.65 m/s^2, and D = 70m. You can easily find Vf. Finally, (Vf - Vi) /(2.65 m/s^2) = t is the time it took to go through the 70 meters.
To remember the above formula, you may think it is from energy conservation:
0.5*m*(Vf)^2 = 0.5*m*(Vi)^2 + (m*a)*D
The final kinetic energy is the sum of the initial kinetic energy and the increase of the kinetic energy.
2007-09-24 17:23:18 · answer #1 · answered by Hahaha 7 · 0⤊ 0⤋