If your car accelerates from rest at a steady rate of 4 m/s2, how soon will it reach 81 km/h (50.3 mph or 22.5 m/s)?
Current velocity = (time)*(acceleration) + initial velocity
22.5 = time*4 + 0
time = 22.5/4 = 5.625 seconds
5.6
To find out how soon the car will reach 81 km/h, we need to determine the time it takes for the car to reach that speed.
We know that the acceleration of the car is 4 m/s², and we want to find the time it takes for the car to reach 81 km/h or 22.5 m/s.
We can use the kinematic equation:
V = V₀ + at
where:
V is the final velocity (22.5 m/s),
V₀ is the initial velocity (0 m/s),
a is the acceleration (4 m/s²), and
t is the time.
Rearranging the equation to solve for t, we have:
t = (V - V₀) / a
Now, substituting the given values into the equation:
t = (22.5 m/s - 0 m/s) / 4 m/s²
Performing the calculation:
t = 22.5 m/s / 4 m/s²
t = 5.625 s
Therefore, it will take approximately 5.625 seconds for the car to reach a speed of 81 km/h (50.3 mph or 22.5 m/s) from rest with a steady acceleration of 4 m/s².