Question

A bicycle was travelling at 20ms-1 when it applied it s brakes and decelerated at a rate of 5ms2.How long will it take before it comes to a stop?how far will it travel before stopping?

Answer 1

Answer:

Explanation:

u=20m/s

a= -5m/s^2

v=0m/s

t=?

we know,

v=u+at

so,

0=20-5t

hence,

t=4 seconds

s= ut+1/2at^2

 = 20x4+1/2x(-5)x16

 = 80-40

 = 40

Answer 2

using v=u+at

0=20-5t

20=5t

4=t

therefore it takes 4 seconds to stop.

v²-u²=2as

0-400=-2(5)s

-400=-10s

10s=400

s=40 m