# Determine what force must be applied to a body of mass m = 60 t moving in a straight line

**Determine what force must be applied to a body of mass m = 60 t moving in a straight line so that on the path S = 1500 m its speed decreases from 25 m / s to 16 m / s.**

m = 60 t = 60,000 kg.

S = 1500 m.

V0 = 25 m / s.

V = 16 m / s.

F -?

According to Newton’s 2 law, the force F, which acts on a body, is equal to the product of the body’s mass m by its acceleration a: F = m * a.

The acceleration of a body with uniformly accelerated motion is found by the formula: a = V ^ 2 – V0 ^ 2/2 * S, where V0, V are the initial and final speed of movement, S is the movement of the body.

a = (16 m / s) ^ 2 – (25 m / s) ^ 2/2 * 1500 m = – 0.123 m / s ^ 2.

The sign “-” means that the acceleration of the body is directed in the opposite direction to the direction of motion, the body is inhibited.

F = 60,000 kg * 0.123 m / s ^ 2 = 7380 N.

Answer: a force F = 7380 N acts on the body.