Question

A test of the prototype of a new automobile
shows that the minimum distance for a controlled stop from 94 km/h to zero is 41 m.
Find the acceleration, assuming it to be
constant as a fraction of the free-fall acceleration. The acceleration due to gravity is
9.81 m/s
2
.
Answer in units of g

How much time does the car take to stop?
Answer in units of s

Answer 1

use one of the equations of constant acceleration
initial velocity u = 94 km / h, final velociy v = 0
distance s = 41 m, a = ?

v^2 = u^2 + 2as
plug in the values for u, v and s and solve for a

oh - you'll need to convert 94 km / hour to m / s
then a will be in m/s

Answer 2

* a will be in m s^-2
divide this by 9.81 to convert to units of g

Answer 3

alright

Answer 4

94 km/h = 94,000 m / h = 94,000 / 3600 = 26.11 m s

Answer 5

yea

Answer 6

how do you find a

Answer 7

so plugging in these vales into the formula:
0 = 26.11^2 + 2a*41
a = -(26.11^2 / 84 negative because the car is slowing down
= -8 .116 m/s_
in terms of g this is -8.116 / 9.81 = -0.827 g

Answer 8

to find time to stop use
v = u + at
0 = 26.11 - 8.116 t
t = 26.11 / 8.116
= 3.22 seconds

Answer 9

do u follow that?
have u got any questions?

Answer 10

no thank you so very much

Answer 11

yw