The speed of a car moving along a horizontal straight section changes according to the law vx = 10 + 5t.

The speed of a car moving along a horizontal straight section changes according to the law vx = 10 + 5t. Calculate the work done by the resultant of all the forces acting on the car if the movement was 1500 m. The mass of the car is 2 tons.

Vx = 10 + 5 * t.

S = 1500 m.

m = 2 t = 2000 kg.

A – ?

The mechanical work A of the resultant force F will be determined by the formula: A = F * S * cosα, where S is the displacement of the body, ∠α is the angle between the resultant force F and displacement S.

With uniformly accelerated motion, the dependence of the speed on time has the form: Vx = V0 + a * t, where V0 is the initial speed, a is the acceleration of the body, t is the time of motion.

V0 = 10 m / s, a = 5 m / s2.

We find the resultant force F according to Newton’s 2 law: F = m * a.

We will assume that the body moves in the direction of the action of the resultant force ∠α = 00, cos00 = 1.

A = m * a * S.

A = 2000 kg * 5 m / s2 * 1500 m = 15,000,000 J = 15 * 10 ^ 6 J = 15 MJ.

Answer: the work of the resultant force is A = 15 * 10 ^ 6 J.