Physics help with forces

[warm ginkgo]

here

[twin wraith]

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[warm ginkgo]

Im doing a

I did time = d/s

I did 0.729km/64.8km/h = 0.01125

0.01125 is 40.5 seconds

64.8km/h/40.5s I got 1.6

-1.6

Since v2 - v1. v2 is 0 and v1 is 64.8

[crisp monolith]

18m/s

[warm ginkgo]

How?

Oh wait I didnt make 64.8 into m/s

[crisp monolith]

0=(18)²+2a(729)

[warm ginkgo]

What is that?

im trying to find acceleration

a = v2-v1/time

[crisp monolith]

v²=u²+2as

[warm ginkgo]

Why would we use that when we have this

[crisp monolith]

we dont have time

[warm ginkgo]

Yea we do

40.5 seconds

[crisp monolith]

how.

[warm ginkgo]

^^^^^

We have distance and speed

[crisp monolith]

driver is braking. so the speed isnt constant to find time

[warm ginkgo]

We can get time

Oh yeah

What is that formula that you used

[crisp monolith]

constantly retarding speed.

[crisp monolith]

3rd equation of motion

[warm ginkgo]

What is u?

[crisp monolith]

initial velocity

v is final velocity

s is displacement

[warm ginkgo]

Alr

Yea this is good formula

[crisp monolith]

want derivation

[warm ginkgo]

I have a hard time determining what formula to use at what time.

[warm ginkgo]

What is that

[crisp monolith]

which year u r in

9th?

[warm ginkgo]

I'm 11th grade

[crisp monolith]

country