Answer:
Frictional force always acts parallel to two planes in contact with each other and in a direction opposite to that of relative motion of the two bodies. 2. Frictional forces are caused due to intermolecular interactions between the bodies. Frictional force is more for rough surface and less for smooth surfaces.
A car starts 10 m north of a reference point. It moves at a constant velocity over the next 5 s, reaching a position of 10 m south of the reference point. What is the car's average velocity?
Answer:
v = -4 m / s
Explanation:
The average speed of a body is defined by the distance traveled in a given time interval
v = (x₂ -x₁) / (t₂ -t₁)
in this case the end point is x₂ = -10 m and the start point is x₁ = 10 m, the negative sign is because the point is below the reference that can be considered as zero point
let's calculate
v = (-10 - 10) / 5
v = -20 / 5
v = -4 m / s