Question

A woman drives 10 miles, accelerating uniformly from rest to 70 mph. How long does it take for her to reach 70 mph?

Answer 1

v = u + at

v = her final velocity
u = her initial velocity
a = acceleration
t = time take (which you are finding)

Answer 2

what's acceleration in this case?

Answer 3

oh sorry.
u need a different equation

Answer 4

hold on

Answer 5

first find her acceration
\[v ^{2} = u ^{2} + 2as\]
then use v = u + at

Answer 6

for kinematics, you need 3 equations and u can solve everything

Answer 7

ill post them for you. copy them somewhere

Answer 8

\[v = u + at\]
\[v ^{2} = u ^{2} + 2as\]
\[s = ut + \frac{ 1 }{ 2 }at ^{2}\]

Answer 9

ok what's s?

Answer 10

s = displacement
remember these are vectors so direction matters as that decides whether the value is positive or negative