A car with a thrust of 0.7 kN moves at a speed of 20 m / s for an hour. Determine engine operation.

F = 0.7 kN = 700 N.

V = 20 m / s.

t = 1 h = 3600 s.

A -?

The mechanical work of force A is determined by the formula: A = F * S * cosα, where F is the engine power of the car, S is the movement of the car, ∠α is the angle between the direction of action of the force F and the movement of S.

Since the thrust force of the engine is directed in the direction of motion, then ∠α = 0, cos0 = 1.

A = F * S.

With uniform rectilinear movement, the movement of the car is expressed by the formula: S = V * t

A = F * V * t.

A = 700 N * 20 m / s * 3600 s = 50400000 J.

Answer: the work of the engine is A = 50,400,000 J.