If a car can go from 0 to 60mi/hr in 8.0 seconds, what would be its final speed after 5.0 seconds if its starting speed were 50mi/hr? My answer was -10, is this correct. If not , I need help
How ever did you get a negative number? I'd assume we are using the same positive acceleration, starting from 50 mph!
assuming constant acceleration, then since the velocity changed by 88ft/s in 8 seconds,
a = 11 ft/s^2
Now to find v, just recall that
v(t) = Vo + at
Just plug in your numbers. I guarantee you will not wind up with -10.
Of course, in the real world, acceleration from a standing start is very different from a starting speed of 50 mph!
oops, didn't find acceleration first(7.5), which is 60 /8. Then 7.5 x 5 + 50=87.5,
a*t+v(starting speed)=final speed
To solve this problem, we need to determine the acceleration of the car. The formula for acceleration is given by:
Acceleration = (Change in Velocity) / (Time)
In this case, the change in velocity is the difference between the final speed and the starting speed, and the time is given as 8 seconds. So we can rewrite the formula as:
Acceleration = (Final Speed - Starting Speed) / Time
We are given that the starting speed is 50 mi/hr, and we want to find the final speed after 5 seconds. To find the final speed, we can rearrange the formula as:
Final Speed = (Acceleration * Time) + Starting Speed
Now, since we know the time is 5 seconds, we can substitute the given values into the equation and solve for the final speed:
Acceleration = (0 - 50) / 8
Acceleration = -6.25 mi/hr/s
Final Speed = (-6.25 mi/hr/s * 5 s) + 50 mi/hr
Final Speed = -31.25 mi/hr + 50 mi/hr
Final Speed = 18.75 mi/hr
So the correct answer is 18.75 mi/hr, not -10 mi/hr. Therefore, your answer of -10 mi/hr is incorrect.