Newton’s Second Law of Motion, Essay Example

Problem: A motorcycle and rider have at total mass equal to 300kg. The rider applies his brakes causing the motorcycle to accelerate at a rate of -5m/s² what is the net force on the motorcycle?  

The problem in this question is in determining the net forces acting on the motorbike. This can be determined by applying Newton’s Second Law of motion which states that the net force acting on a object is equal = mass of the object X its acceleration (F = ma). Hence, in order to determine the net force we have to identify the mass and acceleration of the object. Where the object refers to the rider and motorbike as one mass. The total mass is given as 300kg while the acceleration is given as -5m/s^2. It is of great importance to note that in this case the acceleration is negative implying that the object is decelerating. The negative value gives the direction of the acceleration since acceleration is a vector.

And thus:

F = ma

= 300kg * -5m/s^2

= -1500N

Here, the force is a negative value since force is a vector. The negative value gives the direction of the force and that is opposite to the direction of movement which is brought about by the fact that the motorbike is decelerating.

Problem 2: A motorcycle and rider have at total mass equal to 250kg. The rider applies his brakes causing the motorcycle to accelerate at a rate of 4m/s² what is the net force on the motorcycle?

Since F = ma

Then, F = 300Kg * 6m/s^2

= 1800N

Here, the force is a positive value since force is a vector. The positive value gives the direction of the force and that is in the direction of movement which is brought about by the fact that the motorbike is accelerating.