Could someone please check another one of my answer for me? Thank you!
A commuter backs her car out of her garage with an acceleration of 1.40 m/s2. (a) How long does it take her to reach a speed of 2.00 m/s? (b) If she then brakes to a stop in 0.800 s, what is her deceleration?
a.) V=Vo+at
2.00 m/s = 0 + 1.40 m/s^2t
t = 1.43 seconds
b.) acceleration = v/t
acceleration = (2.00 m/s)/8 s
deceleration = .25 m/s^2
a. Correct!
b. Dec. = (Vf-Vo)/t=(0-2) / 0.8=-2.5 m/s^2.
NOTE: Deceleration is always negative.
a) To answer this question, you can use the equation for acceleration: V = Vo + at, where V is the final velocity, Vo is the initial velocity, a is the acceleration, and t is the time. Since the initial velocity is 0 (the car was initially at rest), the equation becomes V = at.
In this case, the final velocity (V) is given as 2.00 m/s and the acceleration (a) is 1.40 m/s^2. We can substitute these values into the equation: 2.00 m/s = 1.40 m/s^2 * t.
To solve for t, we rearrange the equation: t = V / a = 2.00 m/s / 1.40 m/s^2 = 1.43 seconds.
Therefore, it takes the commuter 1.43 seconds to reach a speed of 2.00 m/s.
b) To find the deceleration, we can use the equation for acceleration: acceleration = v / t, where v is the change in velocity and t is the time it takes to change that velocity.
In this case, the change in velocity is from 2.00 m/s to 0 m/s, which means the final velocity (v) is -2.00 m/s (negative because it's in the opposite direction of the initial velocity). The time (t) is given as 0.800 s.
Substituting these values into the equation, we get: deceleration = (-2.00 m/s) / 0.800 s = -2.50 m/s^2.
The deceleration is -2.50 m/s^2, indicating that the car is slowing down at a rate of 2.50 m/s^2.
a.) To find the time it takes for the commuter to reach a speed of 2.00 m/s, you correctly used the equation V = Vo + at, where V is the final velocity, Vo is the initial velocity, a is the acceleration, and t is the time.
Plugging in the given values:
V = 2.00 m/s
Vo = 0 m/s (since the car starts from rest)
a = 1.40 m/s^2
The equation becomes:
2.00 m/s = 0 + 1.40 m/s^2 * t
Now, solve for t:
t = (2.00 m/s) / (1.40 m/s^2)
t = 1.43 seconds
Therefore, it takes 1.43 seconds for the commuter to reach a speed of 2.00 m/s.
b.) To find the deceleration when the car brakes to a stop, you can use the equation acceleration = change in velocity / time.
The change in velocity is the final velocity (0 m/s) minus the initial velocity (2.00 m/s), which gives us:
change in velocity = 0 m/s - 2.00 m/s = -2.00 m/s
The time taken to decelerate is given as 0.800 seconds.
Plugging in the values:
acceleration = (change in velocity) / time = (-2.00 m/s) / (0.800 s)
acceleration = -2.50 m/s^2
Therefore, the deceleration of the car is -2.50 m/s^2, indicating that it is decelerating at a rate of 2.50 m/s^2.