Question

a car traveling at 50 m/s slams on it's brakes and decelerates at 4 m/s. how much time does the car need to stop? how much distance does the car need in order to stop?​

Answer 1

12.5 s , 312.5 m

Step-by-step explanation:

initial velocity = u= 50 m/s

final velocity= v = 0

acceleration = a - -4 m/s^2

time= t=?

distance = s=?

equation of motion is v = u + at

0r at = v-u

t = (v-u)/a

t= (0-50)/-4

t= -50/-4

t= 12.5 s

s= ut +(1/2)at^2

s= 50(12.5)+(0.5)(-4)(12.5)^2

s=625-312-5

s =312.5 m

Answer 2

Time taken to stop is 12.5 seconds.

Distance travelled is 312.5 m.

Step-by-step explanation:

Initial velocity of the car = u = 50 m/s.

Acceleration of the car = a = -4 m/s² (negative because it decelerates)

Final velocity = v = 0 m/s (as the car stops)

To find:

• time t taken to stop
• distance s travelled till it stops.

By equations of motion:

v = u + at

s = ut+
`(1)/(2)`at²

t =
`(v-u)/(a)=(0-50)/(-4)=12.5\ s`

Hence time taken to stop is 12.5 seconds.

`s=ut+(1)/(2)at^(2)=(50*12.5)+(1)/(2)*-4*(12.5)^(2)=312.5\ m`

Distance travelled is 312.5 m.