Question

cyclist applied breaks to produce an acceleration of 10 meter per second square in the opposite direction of motion if cycle takes 4second to stop after the application of breaks .calculate the distance travelled

Answer 1

Hey there !

Solution :

Acceleration = 10 m / s 

But it is in the opposite direction. Hence Acceleration = - 10 m / s

Time = 4 seconds

Final Velocity ( v ) = 0 m / s

Initial Velocity ( u ) = ?

Equation of motion :

v = u + at

Substituting in the above equation we get,

0 = u + ( - 10 ) ( 4 )

0 = u + ( - 40 )

0 = u - 40

=> u = 40 m / s

But we need to find distance traveled. Hence we know that,

s = ut + $\frac{1}{2} at^2$

Substituting in the above formula we get,

s = 40 ( 4 ) + 1 / 2 ( - 10 ) ( 4 )

s = 160 + 1 / 2 ( - 40 )

s = 160 - 20

s = 140 m

Hence the distance traveled after applying brakes is 140 m.

Hope my answer helped :-)

Answer 2

u=10m/s , a = 10m/s^2 and t = 4sec

therefore, s= ut+1/2at^2
            or, s= 10 *4 + 1/2 *10*4*4
            or, s = 40+80
                      =120  m