Physics question?

Question

please answer this problem and help me understand what to do:

A skater glides off a frozen pond onto a patch of ground at a speed of 1.8 m/s. Here the skater is slowed at a constant rate of 3.00 m/s^2. How fast is the skater moving when she slid 0.37m across the dirt patch?

i really need some help underdtanding these kind of problems. please help, thanks :)

Answer 1

acceleration is how fast the velocity changes:

Vf = Vi + A x T

where:

Vi = initial velocity (1.8 m/s)
Vf = final velocity (which you want to find)
A = acceleration (-3.p m/s^s - minus because you are slowing down)
T = the time between Vi and Vf

So, if you can find T, you can solve for Vf.

The formula that relates time and distance under constant acceleration is

D = Vi x T + (1/2) x A x T^2

In this case you know that D is 0.37 m so you have a quadratic equation in T.

So now you can solve the quadratic for T (don't forget that A is negative) and plug it in to the velocity equation to get the desired result.