(adsbygoogle = window.adsbygoogle || []).push({}); What am I doing wrong???

Question:

A 41 g bullet, with horizontal velocity of 496 m/s, stops 13cm within a soid wall. What is the magnitue of the average Force from the wall stopping it?

This is how i tried to solve it

Vi = 496, Vf=0, and Xf-Xi=.13m

So Vf^2=Vi^2+2a(Xf-Xi)

Which = 0 = 246016+2a(.13)

solve for acceleration you get -946215...

F=m(a)...so i did (-946215)(41) which does not equal the answer? Am i doing anything wrong?

2nd Question:

A girl whose weight is 264 N slides down a 5.8 playground slide that makes an angle of 20degree with the horizontal. The coefficient of kinetic friction is 0.10. If she starts at the top with a speed of 0.457 m/s, what is her speed at the bottom?

This is how i tried to slove it

W= change in U + change in K + change in Thermal

Thermal = 143.98 (i wont show my calculations cause i am 100% sure this is righ)

so..

F(d)= -mgh +(1/2)mv^2 - (1.2)m(.457^2) +143.89

After you plug in all your variables, you have two unkowns,velocity and W.. Provided i did the setup right, how do i figure out the velocity of i dont know the magnitude of her force?

**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: What is the magnitue of the average Force from the wall stopping it?

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