(adsbygoogle = window.adsbygoogle || []).push({}); Differentiation Help!!

1. The problem statement, all variables and given/known data

A particle is moving along a straight line so that, at time t seconds after leaving a fixed point O, its velocity vms-1 is given by v=10sin(1/2 t).

Find the time when the acceleration, given by dv/dt, is first zero.

2. Relevant equations

sinx differentiates to cosx

3. The attempt at a solution

Ok i know they are asking me to find the time where there is a stationary point so therefore the gradient or dv/dt = 0.

From differentiating 10sin(1/2 t) i got 5cos(1/2 t). so therefore, 5cos(1/2 t)=0 so i thought you multiply by 2 to get rid of the half then divide by 10 so the Right hand side= 0 and then inverse cos of 0 = 1/2 Pi but the answer in the textbook gives Pi.

Please help me any body!!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Differentiation Help

**Physics Forums | Science Articles, Homework Help, Discussion**