In a car moving at constant acceleration, you travel 230 m between the instants at which the speedometer reads 40 km/h and 70 km/h how many seconds does it take you to travel the 230 m ?

The relationship between the distance covered, initial and final speeds, and time can be expressed through the equation,

First equation,

                    2ad = Vf² - Vi²

Substituting the known values,
                   2(a)(0.230 km) = (70 km/h)² - (40 km/h)²
The value of a from the equation is 7173.92 km/h².

Second equation,
                   d = (Vi)(t) + 0.5at²

Substituting the known values,
                    0.230 km = (40 km/h)(t) + (0.5)(7173.92 km/h²)(t²)

The value of t from the equation is 4.1818 x 10^-3 hours which is also equal to 0.2509 minutes or 15 seconds.

15 seconds

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j