Question

A car is moving at a speed of 60 m/s, when the driver applies the brakes, which causes a deceleration of 2 m/s2. How many seconds will it take for the car to stop and how far will it travel till it stops?

30 sec, 450 meters
25 sec, 800 meters
30 sec, 1800 meters
20 sec, 900 meters
30 sec, 900 meters

Answer 1

Answer: 30 seconds, 900 meters

Explanation:

in the attachment

Answer 2

Given Information:

Initial velocity = vi = 60 m/s

Final velocity = vf = 0 m/s

Deceleration = a = -2 m/s²

Required Information:

time = t = ?

distance = s = ?

Answer:

time = t = 30 sec

distance = s = 900 meters

Explanation:

We know from the kinematics,

vf = vi + at

at = vf - vi

t = (vf - vi)/a

t = (0 - 60)/-2

t = -60/-2

t = 30 seconds

Now the distance that the car traveled after applying the brakes can be found using the equation,

s = vit + ½at²

s = 60*30 + ½(-2)(30)²

s = 1800 - 900

s = 900 m

Therefore, the correct option is 30 sec and 900 meters