Acar's brakes decelerate it at a rate of -2.10 m/s2. What is the time, in seconds, required to slow the car from 13 m/s to 5.0 m/s?

t = 3.8 [s]

Explanation:

To solve this problem we must use the following equation of kinematics.

where:

Vf = final velocity = 5 [m/s]

Vo = initial velocity = 13 [m/s]

a = desacceleration = 2.1 [m/s²]

t = time [s]

As we can see in the above equation the acceleration is negative because the car slows down its velocity.

5 = 13 - 2.1*t

2.1*t = 13 - 5

t = (8)/2.1

t = 3.8 [s]

ill do it for 100, also this isnt 80 its 40

i had this question and the answer was 3.15 miles.

martina travels from school to her mom's office. from there, she walks to school. after school, she walks to the library and then to a friends house before finally ending back at home. find martina's total distance traveled.

a) 0 miles  

b) 0.4 miles  

c) 1 mile  

d) 3.15 miles