Question

A car traveling at a speed of 45.0 m/s encounters an emergency and comes to a complete stop. If the car accelerates at -4.0 m/s2 , how many seconds will it take for it to come to a complete stop. (Round your answer to the nearest tenths place)

Answer 1

Using the formula v = u + at, we find it takes approximately 11.3 seconds for the car traveling at 45.0 m/s to come to a complete stop with a deceleration of -4.0 m/s^2.

Step-by-step explanation:

To calculate the time it takes for the car to come to a complete stop from a speed of 45.0 m/s while decelerating at -4.0 m/s2, we can use the formula v = u + at, where:

• v is the final velocity (0 m/s, because the car comes to a stop)
• u is the initial velocity (45.0 m/s)
• a is the acceleration (-4.0 m/s2)
• t is the time (what we want to find)

Rearranging the formula to solve for t gives us:

t = (v - u) / a

Substituting the values in:

t = (0 - 45.0 m/s) / (-4.0 m/s2)

t = -45.0 m/s / -4.0 m/s2

t = 11.25 s

Rounding to the nearest tenth, it takes the car approximately 11.3 seconds to stop.

Answer 2

11.3s

Step-by-step explanation:

Using the kinematics equation
`v_f=v_0+at`, we can find the time the car takes to come to a complete stop. Since the car comes to a complete stop, its final velocity (
`v_f`) is 0m/s. Substituting -4.0m/s^2 as
`a` and 45.0m/s as
`v_0`, we can find that t=11.3s.