Final answer:
To calculate the time it takes for the car to reach a velocity of 30 m/s from a stop with an acceleration of 7.8 m/s^2, use the formula t = (v - u) / a, which gives approximately 3.85 seconds.
Step-by-step explanation:
The subject of the question is Physics, specifically the concept of acceleration which falls under kinematics. The grade level is High School as it involves basic motion equations. To find out how long it will take for a car to go from a stop to a velocity of 30 m/s with an acceleration of 7.8 m/s2, we use the formula:
v = u + at
Where:
v is the final velocity (30 m/s),
u is the initial velocity (0 m/s since the car starts from a stop),
a is the acceleration (7.8 m/s2), and
t is the time which we are solving for.
Rearranging the formula to solve for t, we get:
t = (v - u) / a
Substituting the given values:
t = (30 m/s - 0 m/s) / 7.8 m/s2
The car will take approximately 3.85 seconds to reach the velocity of 30 m/s from a stop.