Recent content by Perry

Right, so apparently, i converted 180 km/h wrong. It's actually 50 m/s, not 33.3 m/s. I made another mistake. It's v=120 km/h, not 180.

Right, sorry. Okay so v=180km/h is 33.33 m/s and u=80 km/h is 22.2 m/s. If I plug these numbers into the formula, along with a=-4m/s^2, i get t=2,775 sec. The correct answer is apparently 1.66 sec. I don't know what i am doing wrong.

(mentor note) post moved here from non-homework thread hence no template. A truck is traveling at a v=180 km/h speed on a straight road. At some point, the driver sees a police car and hits the brakes. If his average deceleration is a=-4m/s^2, how long will it take for its speed to go down to...

I enroll as a freshman in physics on september and i have already started studying calculus using thomas finney's textbook. I guess my question is, because the time left is rather limited, should i solve all the practise exercises or should i be more selective? Right now, i am studying the...

I am not sure if this is the right part of the forums to post this, but I was reading the book Surely you're joking Mr Feynman when i reached this part: This got me thinking. How does one "understand" physics and mathematics? It's certainly more than remembering some formulas. What do you think?

Try using ΣF=Δp/Δt. You should find Δt from this equation. Then you use this one to find the acceleration: v=u-at. Can you find out what comes next?