The picture above illustrates the horizontal forces acting on a car. The car’s engine force pushes forward, while friction between the tires and the road, along with wind resistance drag at the car in the backwards direction. Which of the following must be true about these forces if the car is driving forward on a level road at a constant speed of 45 miles per hour?

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

Aparticle's position is given by x = 3.00 - 9.00t + 3t2, in which x is in meters and t is in seconds. (a) what is its velocity at t = 1 s? (b) is it moving in the positive or negative direction of x just then? (c) what is its speed just then? (d) is the speed increasing or decreasing just then? (try answering the next two questions without further calculation.) (e) is there ever an instant when the velocity is zero? if so, give the time t; if not, answer "0". (f) is there a time after t = 3 s when the particle is moving in the negative direction of x? if so, give the time t; if not, answer "0".

Atruck driver is attempting to deliver some furniture. first, he travels 8 km east, and then he turns around and travels 3 km west. finally, he turns again and travels 13 km to his destination. what is the drivers distance