A driver of a car traveling at 17.4 m/s applies
the brakes, causing a uniform deceleration of
1.8 m/s2
.
How long does it take the car to accelerate
to a final speed of 13.4 m/s?
Answer in units of s.
vf=vi+a*time
you are given a as -1.8m/s^2, vf=0, vi=17.4m/s solve for time t.
u = 17.4m/s, a = -1.8m/s^2
v = 13.4m/s
Using the first equation of motion:
=> v = u + at
=> (v-u)/a = t
=> -4/-1.8 = t
=> 2.22 seconds
Arora: When you give it away free, it has no value.
Hope you've heard about equations of motion.
For this one we can use v=u+at , where v=final velocity(in m/s) , u=initial velocity(in m/s) , a=uniform acceleration(in m/S^2) and t=time(in seconds).
Now substitute values for the above equation to find the required time.
To find the time it takes for the car to accelerate to a final speed of 13.4 m/s, we need to use the equation for uniformly accelerated motion:
v = u + at
Where:
v = final velocity
u = initial velocity
a = acceleration
t = time
In this case, the initial velocity (u) is 17.4 m/s, the final velocity (v) is 13.4 m/s, and the acceleration (a) is -1.8 m/s² (negative because it is deceleration).
Rearranging the equation, we get:
t = (v - u) / a
Plugging in the values:
t = (13.4 m/s - 17.4 m/s) / -1.8 m/s²
Simplifying:
t = -4 m/s / -1.8 m/s²
The unit "m/s" cancels out, leaving us with:
t = 4 / 1.8 s
Calculating the result:
t ≈ 2.22 s
Therefore, it takes approximately 2.22 seconds for the car to accelerate to a final speed of 13.4 m/s.