Question

A cyclist is travelling at 15ms −1.
She applies brakes so that she does not collide with a wall 18m away. What deceleration must she have?
Please give the answer relating to equations of motion of acceleration = v-u/t
If you just tell the time somehow I could do it myself but please fast​

pls report this question and get it deleted

Answer 1

Initial velocity, u=15m/s

Final velocity, v=0m/s

Distance, s=18m

Acceleration, a=?

Using relation, v²-u²=2as

0²-(15)²=2a × 18 -225= 36a

a= -225/36= -6.25m/s²

Answer 2

Initial velocity, u=15m/s

Final velocity, v=0m/s

Distance, s=18m

Acceleration, a=?

Using relation, v

2

−u

2

=2as

0

2

−(15)

2

=2a×18

−225=36a

a=

36

−225

=−6.25m/s

2

So, deceleration is 6.25m/s

2

.