What is the acceleration of a vehicle that changes its velocity from 120 km/h to a dead stop in 7 s?
Answer in km/h·s
(120 km/h)divided by 7s will give you the answer in units of km/(h.s)
I think it's the wrong answer because I plugged it in and it was still marked wrong.
I would use two significant figures and choose 17 km/h.s for the answer. If it isn't accepted, there is something wrong with test grading system
you must convert it to m/s
To find the acceleration of a vehicle, we need to use the equation for acceleration:
acceleration = (final velocity - initial velocity) / time
In this case, the initial velocity is 120 km/h, the final velocity is 0 km/h (since the vehicle comes to a dead stop), and the time taken is 7 s.
Let's calculate the acceleration step by step:
1. Convert the velocities from km/h to km/s. Since we need the answer in km/h·s, it's important to have the velocity in km/s for consistency. We know that 1 km/h is equal to 1/3600 km/s.
Initial velocity in km/s = 120 km/h * (1/3600 km/s) = 0.03333 km/s
Final velocity in km/s = 0 km/h * (1/3600 km/s) = 0 km/s
2. Plug the values into the acceleration formula:
acceleration = (final velocity - initial velocity) / time
= (0 km/s - 0.03333 km/s) / 7 s
3. Calculate the difference in velocity:
final velocity - initial velocity = 0 km/s - 0.03333 km/s = -0.03333 km/s
4. Substitute the values into the formula:
acceleration = (-0.03333 km/s) / 7 s
5. Calculate the acceleration:
acceleration = -0.00476 km/s²
Therefore, the acceleration of the vehicle, when it changes its velocity from 120 km/h to a dead stop in 7 s, is approximately -0.00476 km/h·s.