12. The diagram shows the forces acting on a lorry as it travels along a flat road. 5000 N
1200 N
1300 N
IT
5000 N
a
Two of the forces have effects that cancel each other out. Which two? Explain your answer.
b What is the resultant force acting on the lorry? Give its magnitude and direction.
What effect will this resultant force have on the speed at which the lorry is travelling?
12]
[3]

Answertraveling around a circular trackexplanation"traveling around a circular track" is the best answer as you could be traveling around a circular track at a constant speed. your velocity would therefore have the same magnitude but will always be constantly direction. since acceleration is the rate of change of velocity, the rate of change will only involve the direction of velocity and not the magnitude.wrong choices: "an object at rest" does not accelerate at all"increasing speed while traveling around a curve" means that the acceleration will not be constant due to only change in direction; it will be constant due to both magnitude and direction"an object in free fall" does not necessarily change direction 

Answerthe force between the charges will be  f/9 (one-ninth of force f)explanationcoulomb's law relates the magnitudes  two point charges q₁ and q₂, the distance, r, between the charges, and the electrostatic force, f, between the two charges:     k represents coulomb's constant, k = 8.99×10⁹ n·m²/c².note that if we have r = 3r, then   

The chemical reactions lab we did is typically called a "copper plating lab,  because the acid solution cleaned the pennies and made the copper look shinier;   the acid solution cleaned the paperclips and made them look like pennies;   &   the copper from the pennies was removed, and then added to the paperclips. 

F  you double the  force, you double the acceleration, but  if  you double the  mass, you velocity. all bodies accelerate at the  same  rate regardless of size or  mass.